Article

The behaviour of broiler chickens and its modification by lameness

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Abstract

The behaviour of six replicates of broilers obtained from commercial farms, fed ad-libitum and housed on 23-h light:1-h dark schedule at 20 lx was observed using scan sampling. Comparisons were made between sound birds and those of varying degrees of lameness between 39 and 49 days of age. Sound broilers averaged 76% of their time lying and this increased significantly to 86% in lame birds (gait score 3). Lying also increased with age. Although sound broilers spent only a minor part of the day on their feet, they spent significantly more time standing idle (7%), standing preening (3.5%) and standing eating (4.7%) than lame birds. Walking declined with age, but occupied an average 3.3% of the time of a slaughter-weight broiler. Again, lameness significantly reduced this to a minimal 1.5% in the worst affected birds. Sound birds predominantly chose the usual standing posture for eating, whereas, lame birds lay down to eat for almost half their feeding time. Detailed observations using video records revealed that lameness altered the feeding strategy of broilers. Whereas sound birds fed over 50 times in 24 h, the number of visits to the feeder was reduced with increasing lameness to an average of around 30 in the lamest broilers. However, meal duration was adjusted to give no overall differences in time spent feeding per day. Time spent drinking was also the same for all birds, averaging 3% of the day. The alterations of the time budget, in particular the reductions in activities performed whilst standing, and the different feeding strategies adopted, are consistent with lameness imposing a cost on the affected broilers to the detriment of their welfare.

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... This suggests that these types of enrichments are important to fulfil natural behaviors, but current broiler houses mostly lack any form of enrichment. Several studies assessing behaviour showed that fast-growing broiler chickens spend approximately 80% of their lifespan with passive behaviours (e.g., lying, sitting and resting) [4,18,24]. The lack of activity, together with a fast growth rate, may impair bone development, which is one of the reasons for suboptimal leg health and lameness [12,18,[25][26][27]. ...
... One of the reasons is that the speed of bone development is unable to keep up with this rapidly increased body weight in fast-growing broiler chickens and they have more porous and less mineralised bones than slower-growing broiler chickens [44, 45]. It has been found that slower-growing broiler chickens spent more time on perches and platforms [46, 47], demonstrated better locomotion [24,26, 46,[48][49][50], had less hock and leg problems [46,51] and lower mortality [52] than fast-growing broiler chickens. ...
... One of the most important underlying reasons for suboptimal bone development in broiler chickens is high growth rate, while low activity levels is the other one [12,24,41]. The hypothesis of this study was that leg health and bone characteristics in broiler chickens can be improved through pen enrichment, which has previously been confirmed by several studies [21,30,31,33,35]. ...
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Pen enrichment for broiler chickens is one of the potential strategies to stimulate locomotion and consequently contribute to better leg health and welfare. This study was designed to evaluate effects of using a plethora of pen enrichments (barrier perches, angular ramps, horizontal platforms, large distance between feed and water and providing live Black Soldier fly larvae in a dustbathing area) on tibia characteristics, locomotion, leg health and home pen behaviour of fast and slower-growing broiler chickens. The experiment was set up as a 2 x 2 factorial arrangement with a total of 840 male broiler chickens in a complete randomized design (7 pens per treatment and 30 chickens per pen) with the following treatments: 1) pen enrichment (enriched pen or non-enriched pen); 2) broiler strain (fast-growing Ross 308 or slower-growing Hubbard JA 757). Home pen behaviour and use of enrichment were observed. At approximately 1400 and 2200 g body weight, two chickens per pen were randomly selected and slaughtered, to investigate tibia morphological, biophysical and mechanical characteristics and leg health. Pen enrichment positively affected tibia biophysical characteristics, e.g., osseous volume (Δ = 1.8 cm ³ , P = 0.003), total volume (Δ = 1.4 cm ³ , P = 0.03) and volume fraction (Δ = 0.02%, P = 0.002), in both fast and slower-growing chickens, suggesting that pen enrichment particularly affects ossification and mineralization mechanisms. Accordingly, locomotion and active behaviours were positively influenced by pen enrichment. However, pen enrichment resulted in lower body weight gain in both strains, which might be due to higher activity or lower feed intake as a result of difficulties of crossing the barrier perches. Regarding the strain, slower-growing chickens showed consistently more advanced tibia characteristics and more active behaviour than fast-growing chickens. It can be concluded that pen enrichment may lead to more activity and better bone development in both fast and slower-growing chickens.
... In a UK survey by Knowles et al. (2008) it was reported that 27.6% of the birds represented in the survey had a gait score of 3 (i.e., obvious gait defect which affects the ability to move about (Kestin et al., 1992)) or higher at an average age of 40 d, although there was considerable variation between flocks. Leg weakness may negatively affect the birds' welfare, as there are indications that leg weakness might be painful for the affected birds and, in severe cases, birds may have difficulties competing with others for resources and may be limited in performing specific behaviors (Kestin et al., 1992), such as dustbathing or preening while standing (Vestergaard and Sanotra, 1999;Weeks et al., 2000). Furthermore, lameness can have economic consequences for farmers. ...
... locomotor activity compared to birds with a good gait. This decrease in activity levels for SG birds, that is, birds with gait score 3 or higher, matches reports in literature in which lower activity levels for birds with higher gait scores were reported (e.g., Weeks et al., 2000;Van Hertem et al., 2018). This often-reported negative relationship between activity level and gait score can have different underlying causes that are difficult to separate from each other. ...
... It is important to note, however, that the slope values were approached using linear regression, which may have masked some of the nuances in the patterns over time. In a study by Weeks et al. (2000), birds with gaits ranging from gait score 0 to 3 were observed on 6 d between 39 and 49 days old. Exactly which 6 d these were, was not specified further. ...
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Gait, or walking ability, is an often-measured trait in broilers. Individual gait scores are generally determined manually, which can be time-consuming and subjective. Automated methods of scoring gait are available, but are often implemented at the group level. However, there is an interest in automated methods of scoring gait at the individual level. We hypothesized that locomotor activity could serve as a proxy for gait of individual broilers. Locomotor activity of 137 group-housed broilers from four crosses was recorded from approximately 16 to 32 days old, using an ultra-wideband tracking system. These birds were divided over four trials. Individual gait scores were determined at the end of the tracking period, on a scale from zero to five, with higher scores representing worse gait. Given the limited number of birds, birds were subsequently categorized as having a good gait (GG; scores 0 to 2) or a suboptimal gait (SG; scores 3 to 5). Relationships between activity and gait classification were studied to determine whether individual activity has the potential to serve as a proxy for gait. When comparing GG and SG birds using robust linear regression, SG birds showed a lower 1) activity around the start of tracking (estimate = -1.33 ± 0.56, p = 0.019), 2) activity near the end of tracking (estimate = -1.63 ± 0.38, p < 0.001), and 3) average activity (estimate = -1.12 ± 0.41, p = 0.007). When taking day of tracking, trial, cross and body weight category (heavy versus light at approximately two weeks old) into account, a tendency was still observed for SG birds having lower activity levels within lightweight birds, but not within heavyweight birds. This study provides indications for activity differences between gait classifications. However, given that there was considerable overlap in activity levels between the gait classifications, future research implementing additional activity-related variables is required to allow a more complete distinction between birds with different gait classifications.
... Primarily among broiler welfare issues are leg disorders affecting nearly one-third of commercial birds, who show reduced ability to walk and access resources (Knowles et al., 2008;Bassler et al., 2013). Lame broilers aged 6-7 weeks spend close to 90% of their daily time budget inactive, and spend only 1.5% of time active, compared to 3.3% of time active in sound birds (Weeks et al., 2000). This extended time spent lying in contact with the litter can result in contact dermatitis, and ultimately culls if the birds cannot access feed and water (Weeks et al., 2000;Nääs et al., 2009;Bassler et al., 2013). ...
... Lame broilers aged 6-7 weeks spend close to 90% of their daily time budget inactive, and spend only 1.5% of time active, compared to 3.3% of time active in sound birds (Weeks et al., 2000). This extended time spent lying in contact with the litter can result in contact dermatitis, and ultimately culls if the birds cannot access feed and water (Weeks et al., 2000;Nääs et al., 2009;Bassler et al., 2013). Culls are estimated to cause 2% loss in a $30 billion industry (Dunkley, 2007;USDA., 2019). ...
... Leg disorders are exacerbated by characteristic inactivity (Weeks et al., 2000), and lack of exercise hinders leg skeletal development and weight-bearing ability (Lanyon, 1993;Rath et al., 2000). In other words, skeletal disorders partially caused by lack of exercise cause lameness, which itself causes inactivity. ...
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Genetic selection for fast growth rate and high breast muscle yield in modern broilers has unintended effects on animal welfare and behavior, namely in terms of inactivity and leg disorders. We hypothesized that exercise stimulated through environmental enrichment could positively stimulate pen-wide activity and improve bird welfare. The study objectives were to implement a laser enrichment device to motivate active and feeding behaviors throughout the pen. Twelve hundred Ross 708 broilers were randomly assigned to enrichment (LASER; laser enrichment, or CON; no laser enrichment) for 49 d. Seventy focal birds were randomly assigned to 14 video-recorded pens for behavioral analysis, including focal bird home pen behavior and walking distance. Pen-wide activity was also measured during the 4-min laser periods, four times daily, d0–8, and 1 day weekly, wk 1–6. Focal birds were gait scored wk 1–6, and were euthanized on d42 for tibia bone mineral content, density, and bone breaking strength analysis. Time spent active was increased in LASER-enriched birds compared to CON on wk 3–5 by up to 214% (wk 4), and percent of time at the feeder was increased in LASER-enriched birds by 761% on wk 4 ( P < 0.05). Peak percent of birds following the laser (LASER-enriched pens only) was observed on d0 (8.52%). Over wk 1–6, peak laser-following behavior was observed on wk 3 (3.07% of birds). Percent of birds moving during laser periods was increased in LASER-enriched pens on d0, 1, 2, 6, 7, and 8, with a percent increase of 68.7% observed on d1 ( P < 0.05). Percent of birds moving (laser-following or not) was increased on wk 1, 3, and 4 in LASER-enriched pens, with an increase of 69.7% observed on wk 4 ( P < 0.05). No differences were found in tibia measures. These data indicate that laser enrichment stimulated voluntary locomotion through wk 5 and laser-following behavior through wk 6, and that the relatively small percent of birds actively following the laser stimulated pen-wide movement above the level of the CON through wk 4 on study.
... Leg weakness is a general term to describe multiple pathological states resulting in impaired walking ability in broilers (Butterworth, 1999). This impaired walking ability may affect birds' welfare through, for example, the potentially associated pain and resulting difficulty with competing for resources and performing specific behaviours (Kestin et al., 1992), such as dustbathing or preening while standing (Vestergaard and Sanotra, 1999;Weeks et al., 2000). ...
... Furthermore, it has been shown that there is a relationship between body weight and gait score, with heavier birds often having a higher gait score (i.e., a worse gait; Kestin et al., 2001). Weeks et al. (2000) compared gait scores 0, 1, 2 and 3 (ranging from no detectable abnormality to an obvious gait defect (Kestin et al., 1992)) and found that the birds with higher gait scores spent less time walking. Possibly, the increasing weight of the birds over time could result in a decrease in distance moved as a consequence of these higher gait scores, but this cannot be concluded from the current study and the relationship between activity, gait and weight at the individual level requires further investigation. ...
... In a UK survey by Knowles et al. (2008) it was reported that 27.6% of the birds represented in the survey had a gait score of 3 (i.e., obvious gait defect which affects the ability to move about (Kestin et al., 1992)) or higher at an average age of 40 d, although there was considerable variation between flocks. Leg weakness may negatively affect the birds' welfare, as there are indications that leg weakness might be painful for the affected birds and, in severe cases, birds may have difficulties competing with others for resources and may be limited in performing specific behaviors (Kestin et al., 1992), such as dustbathing or preening while standing (Vestergaard and Sanotra, 1999;Weeks et al., 2000). Furthermore, lameness can have economic consequences for farmers. ...
... However, this heavy body weight reached over a short time frame has been linked to the development of bone abnormalities and lameness (Julian, 1998;Bradshaw et al., 2002;Kierończyk et al., 2017) Lameness is a broad term used to describe impaired walking ability and several debilitating conditions, resulting from multifactorial origins Bradshaw et al., 2002;Kierończyk et al., 2017). Lame birds commonly show reduced walking ability, difficulty standing, prolonged, frequent squatting while walking, and reduced ability to perform natural and active behaviors the birds may be motivated to perform, leading to frustration (Julian, 1998;McGeown et al., 1999;Weeks et al., 2000;Danbury et al., 2000;Dawkins et al., 2009;Caplen et al., 2013;Vasdal et al., 2018;Norring et al., 2019;Rayner et al., 2020). Lameness can be caused by injuries, trauma, infectious, and non-infectious factors, which can affect bones, muscle, skin, or the nervous system (Bradshaw et al., 2002;Kierończyk et al., 2017). ...
... The Bristol six-point gait scoring system developed by Kestin et al. (1992) is the most widely used methodology to investigate walking ability and lameness in broiler chickens (Caplen et al., 2012). Scores equal to or greater than 3 are assumed to be painful, indicating that the welfare of birds may be compromised (McGeown et al., 1999;Weeks et al., 2000;Knowles et al., 2008;Caplen et al., 2013;Hartcher and Lum, 2020). Despite the widespread use of the Bristol gait scoring scheme to assess lameness in commercial broiler flocks at farm and research settings, this method provides a subjective estimation of birds' walking ability and requires observers to classify the different degrees of gait problems. ...
... Although the number of visits to the feeder was not evaluated, these findings suggest that the categories and strains evaluated in our study organized their feeding similarly. Weeks et al. (2000) reported significant changes in feeding behavior in lame birds, with a decrease in visits to the feeder but increased duration of feeding per bout compared to sound birds, resulting in a similar total time spent feeding per day, despite the differences in feeding strategies. Nevertheless, it is unclear if the differences in total obstacle crossings between SLOW and other categories in our study occurred in response to lameness. ...
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In this study, the mobility, incidence, and severity of contact dermatitis and litter moisture content were assessed in 14 strains of broiler chickens differing in growth rate. The strains encompassed 2 conventional (CONV; ADG 0-48 >60 g/d) and 12 slower-growing (SG) strains categorized as FAST (ADG 0-62 =53-55 g/d), MOD (ADG 0-62 =50-51 g/d), and SLOW (ADG 0-62 <50 g/d), with 4 strains in each category. A total of 7,216 mixed-sex birds were equally allocated into 164 pens (44 birds/pen; 30 kg/m 2) in a randomized incomplete block design, with each strain represented in 8-12 pens over 2-3 trials. From each pen, 4-6 birds were tested in the latency-to-lie (LTL) and group obstacle tests one week prior to the birds reaching 2 target weights (TWs) of approximately 2.1 kg (TW1: 34 d for CONV and 48 d for SG strains) and 3.2 kg (TW2: 48 d for CONV and 62 d for SG strains). The incidence of footpad dermatitis (FPD) and hock burns (HB) were evaluated a day prior to each TW. Litter moisture content was determined biweekly from d 14 to d 56. At TW1, CONV and SLOW had longer LTL than FAST birds. At TW2, CONV, MOD, and FAST birds had similar LTL. At both TWs, CONV birds were lighter than FAST birds in the group obstacle test, yet their number of obstacle crossings was similar. At TW1, CONV birds had greater incidence of FPD than FAST and MOD, while at TW2, CONV birds had greater incidence than the other categories. The incidence of HB in CONV and MOD was greater than SLOW birds at TW1, while at TW2, the incidence of HB was greater in CONV and FAST birds vs. MOD and SLOW birds. Litter moisture content was high in all categories from d 28 onwards. Our results indicate that both BW and growth rate influence leg strength and walking ability, whereas the overall high litter moisture content and to a lesser extent growth rate influenced the incidence of contact dermatitis.
... This efficient growth, in combination with the relatively high body weight and low activity level, has been associated with the development of leg problems: impaired walking ability (Bessei, 2006;EFSA, 2010;Tahamtani et al., 2018) and contact dermatitis on feet and hocks (Bessei, 2006;EFSA, 2010). Leg problems have a negative effect on broiler welfare, because of pain and discomfort and difficulties to perform natural behaviours (Mc Geown et al., 1999;Weeks et al., 2000; Abbreviations: BSFL, black soldier fly larvae; EE, enriched environment; NE, non-enriched environment; SLOW, slower-growing broiler strain; FAST, fast-growing broiler strain. Caplen et al., 2013;Hothersall et al., 2016). ...
... Fast-and slower-growing broilers are selected for a specific growth rate and differences between strains with regard to time budgets are most likely a result of growth or weight differences (Bokkers and Koene, 2003;Wallenbeck et al., 2016). Differences in activity might also be related with the presence of leg problems, since they may cause pain or physical limitations (Mc Geown et al., 1999;Weeks et al., 2000;Caplen et al., 2013;Hothersall et al., 2016). However, in the current study strains did not differ in gait scores, footpad dermatitis or hock burns. ...
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Effects of environmental enrichment on activity, behaviour, walking ability, contact dermatitis and performance were investigated in fast- and slower-growing broiler chickens. A total of 840 day-old male broilers, 420 of a fast-growing strain (Ross 308) and 420 of a slower-growing strain (Hubbard JA757), were housed in a 2 × 2 factorial arrangement, using a complete randomized design. Broilers were housed in 28 pens of 3 m2 in one climate-controlled room. Half of the pens per strain were enriched (EE) with barrier perches, ramps, platforms and a dustbathing area, and the other half of the pens were not enriched (NE). In the EE pens, also black soldier fly larvae were provided daily in the dustbathing area and broilers in NE pens received an additional protein-fat mix, to achieve similar energy and nutrient intake compared to the EE treatment. Behaviour was observed by scan sampling and focal sampling in weeks 2, 4, 5 and 7. Walking ability, footpad dermatitis and hock burn were measured in three broilers per pen at a body weight of 1.7 and 2.6 kg. Performance was determined weekly. Results showed that in the enriched environment, at the same age slower-growing broilers made more use of provided enrichment materials than fast-growing broilers (P < 0.001; Δ = +13.5 %). Providing enrichment decreased the proportion of slower-growing chickens standing idle, whereas this effect was not found for fast-growing broiler chickens (P = 0.006; Δ = -2.8 % for slower-growing broilers). Furthermore, at the same age, more slower-growing broilers were active (Δ = +4.5 %) compared to fast-growing broilers, whereas fast-growing broilers showed more sitting idle (Δ = +4.2 %) and ingestion behaviour (Δ = +2.8 %) than slower-growing broilers in both EE and NE pens (P
... Fast-growing ("conventional") broilers also have low activity levels. Broilers can spend as much as 70 to 80% of their day sitting (Bizeray et al., 2000;Weeks et al., 2000;Bokkers and Koene, 2003;Dixon, 2020), whereas their ancestors, red junglefowl, spend as little as 10% of their day sitting (Dawkins, 1989). Low locomotor activity, or inactivity, is not a welfare concern in and of itself; however, inactivity may cause or be caused by broiler welfare issues. ...
... As expected, all broiler strains eventually reached high levels of inactivity, equivalent to approximately 78 to 80% of the day, despite being provided with enrichment objects that may increase activity. Other research, based on behavioral observations, has shown that conventional birds spend 70 to 86% of their time performing inactive behaviors (e.g., Weeks et al., 2000;Bokkers and Koene, 2003;Alvino et al., 2009;Bailie et al., 2013;Dixon, 2020). Few studies have raised slower growing broilers to 62 days of age; however, one study noted that older slower growing broilers (>7 wk of age) spent 68% of observations sitting and lying (Bokkers and Koene, 2003). ...
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Selection for rapid growth has produced heavier, more efficient broiler chickens, but has also introduced health and welfare issues, which may cause or be caused by inactivity. Rapid growth may also limit the performance of motivated behaviors, whereas the provision of enrichment may increase these behaviors and general activity. This study aimed to evaluate the inactivity, behavior patterns, and enrichment use of 2 fast- (CONV) and 12 slower-growing broiler strains [categorized as fastest (FAST), moderate (MOD) and slowest slow (SLOW), based on their growth rates; 4 strains/category]. To evaluate inactivity, one male and one female from 153 pens were outfitted with omni-directional accelerometers from day 21 until processing (14–24 birds/strain from 8-12 pens/strain). Additionally, to supplement inactivity data, five-minute continuous behavioral observations of four focal birds per pen (2 males, 2 females) were conducted on days 26, 42, and 56 (72–148 observations of 8–12 pens/strain) to quantify the duration and frequency of various behaviors; at the same time, 5–11 instantaneous scan samples were also performed for pen-based enrichment use. Inactivity peaked at 78-80% of the day for all strains; however, those with slower growth rates reached these levels at older ages. Compared to slower-growing strains at the same age, faster-growing strains were more inactive, spent more time sitting and feeding, spent less time standing and walking, and used enrichments less; these differences mostly occurred at younger ages. Generally, at the same age, strains with similar growth rates (within the same category) behaved similarly, with only a few exceptions. Results suggest that not all strains identified as ‘slow-growing’ broilers behave differently from fast-growing broilers, nor do they all behave similarly to each other. As such, results suggest that improved broiler welfare, particularly with respect to reduced inactivity, the performance of a wider range of normal, motivated behaviors, and/or increased enrichment use, is related to the broiler strain's specific growth rate.
... Moreover, the frequency and time spent eating, sitting or standing have been measured as patterns of chicken overall activity (Hocking et al., 1997). The cumulative time for standing and sitting has been useful for the study of normal posture, locomotion, leg disorders, lameness studies, and other physical problems associated to broilers (Weeks et al., 2000;Bokkers and Koene, 2003). ...
... Eating, drinking and walking behaviors are increased in the morning time in broilers (Bayram and € Ozkan, 2010). The discrepancies with our results might be explained for the potential effects of other factors such as body weight, age, feed quality, feed particle size and photoperiod (Yo et al., 1997;Weeks et al., 2000). ...
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Ghrelin is a hormone that induces orexigenic effects in mammals. However, in avian species, there is scant and conflictive results on the effect of ghrelin on feed intake (FI). Therefore, we evaluated the effect of a ghrelin receptor agonist (capromorelin) on FI, ADG, water intake (WI), animal behavior and concentrations of ghrelin, glucose, growth hormone (GH) and insulin in broiler chickens. One-day-old male broilers were reared as recommended by the industry. At 4 wk of age (experimental day 0; D0), birds were blocked by weight and randomly assigned to 3 treatments in 2 identical trials. Control birds received a vehicle control solution containing 0 mg/kgBW/d of capromorelin. Birds in treatments 2 and 3 received capromorelin at target doses of 6 or 12 mg/kgBW/d of capromorelin (n = 27). FI and WI were measured 3 times a day at 0700 h (Period 1; P1), 1200 h (P2) and 1700 h (P3), while BW was recorded daily. Blood samples were collected on D-1 and D5. Bird behavior (pecking, sitting and standing) was evaluated for 9 h on D2. Data were analyzed using a randomized complete block design with repeated measures over time. Orthogonal polynomial contrasts were used to determine linear and quadratic effects of increasing levels of capromorelin. Polynomial contrasts showed that capromorelin doses linearly increased FI (P = 0.002) and ADG (P = 0.019). There were no treatment, day or treatment x d interactions on glucose, ghrelin and GH concentrations. However, there was a treatment x d interaction (P = 0.041) on insulin concentrations. Concentrations of insulin were higher on D5 for the 0 and 12 mg/kgBW/d treatments as compared with D-1. Polynomial contrasts showed that capromorelin doses linearly increased number of pecks/h (P = 0.018). Per hour FI and WI was higher during P1 (i.e., 0700-1200) as compared to P2 and P3 (P < 0.001). Our observations suggest that capromorelin linearly increases feed intake; thus, the same effect of that reported in mammalian species.
... Swift growth and a disproportionate amount of breast muscle have inadvertently altered the bird's center of gravity (Havenstein et al., 2003) and led to welfare and meat quality issues. Predominant welfare concerns include leg lameness and lack of activity (Dunkley, 2007;Knowles et al., 2008;Bassler et al., 2013) which lead to contact dermatitis, further inactivity, and increased culls (Weeks et al., 2000;Nääs et al., 2009). Litter-contact driven dermatitis of the breasts and footpads results in a chemical burn effect that is likely painful (Haslam et al., 2006). ...
... Exercise has previously been associated with poorer feed conversion in egg-laying chicken strains (Akbar et al., 1985), and has been shown to have no effect on body weight or FCR in broilers, whether stimulated by lighting (Prayitno et al., 1997) or by increasing distance between resources (Reiter and Bessei, 2009;Ruiz-Feria et al., 2014). Modern broilers are reported to spend the vast majority of their time inactive, and only 3.3% of the day walking as they near market weight (Weeks et al., 2000). This is believed to be the result of an unenriched environment (Newberry, 1999), exercise-limiting stocking density (Sorensen et al., 2000), and genetic selection for a large proportion of breast and body weight associated with skeletal disorders (Kestin et al., 1992). ...
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Sustainability in poultry production is evident in efforts to reduce inputs and a focus on bird welfare and livability. Dietary protein alternatives to traditional sources such as soybean meal aim to meet or exceed efficiency benchmarks and be cost-effective. Environmental enrichment encouraging activity may reduce the occurrence of the predominant breast muscle myopathy, woody breast (WB); interventions to minimize muscle damage and economic loss have yet to be established. The study objectives were to maintain or improve broiler performance and breast quality through environmental enrichment and partially replacing dietary soybean meal with Spirulina. Twelve hundred Ross 708 broilers were randomly assigned to enrichment (LASER; laser enrichment, or CON; no laser enrichment) and diet (algae; 2.5% Spirulina algae, or control) in a 2 × 2 factorial design for 49 days. The same 70 randomly selected birds were examined for contact dermatitis wk 1–6. Breast width was measured weekly on 200 growing broilers beginning on d22. On d42 and 49 slaughter, WB score was assigned using a tactile 0–3 scale and the right breast filet was weighed ( n = 200). RNA isolated from 30 breast muscle samples each at d42 and 49 was analyzed using real-time qPCR. Laser enrichment increased body weight at all timepoints (d49: 0.148 kg, P < 0.001). Feed conversion ratio was improved in LASER-enriched birds by 3 points in the starter period ( P = 0.003). Breast width was increased at all timepoints in LASER-enriched birds compared to CON (d49: 0.47 cm, P < 0.001). Algae inclusion increased body weight at d28 (0.059 kg, P = 0.005). At d42, 12% more LASER-enriched WB scores were 0 (normal) compared to CON, and at d49, 15% more enriched scores were 0. At d42, 5% more algae-fed broiler scores were 0 compared to control. LASER-enriched broiler breast tissue showed upregulated expression of myogenin, muscle regulatory factor 4, insulin-like growth factor 1, and myostatin compared to CON ( P < 0.01). Both laser enrichment and algae inclusion improved broiler performance without negatively impacting environmental or physiological outcomes. LASER enrichment decreased severity of WB score and positively shifted myogenic gene expression in the breast muscle at slaughter.
... The final data set was composed of 1 behavioral attribute that can assume 12 different values (Table 3) corresponding to the elaborated ethogram consisting of basic behaviors, based on previous studies related to the behavior and welfare of broilers [12,27,28]. The thermal stress consisted of a temperature 8 °C above the thermoneutral temperature for the birds' age ( Table 2). ...
... Previous studies show that broilers spend 60 to 80% of their time resting [27,29,40]. However, aging birds decrease their activities, especially their locomotor and floorscratching activities [30,46] and their rapid growth rate [28]. ...
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Broiler productivity is dependent on a range of variables; among them, the rearing environment is a significant factor for proper well-being and productivity. Behavior indicates the bird’s initial response to an adverse environment and is capable of providing an indicator of well-being in real-time. The present study aims to identify and characterize the sequential pattern of broilers’ behavior when exposed to thermoneutral conditions (TNZ) and thermal stress (HS) by constant heat. The research was carried out in a climatic chamber with 18 broilers under thermoneutral conditions and heat stress for three consecutive days (at three different ages). The behavior database was first analyzed using one-way ANOVA, Tukey test by age, and Boxplot graphs, and then the sequence of the behaviors was evaluated using the generalized sequential pattern (GSP) algorithm. We were able to predict behavioral patterns at the different temperatures assessed from the behavioral sequences. Birds in HS were prostrate, identified by the shorter behavioral sequence, such as the {Lying down, Eating} pattern, unlike TNZ ({Lying down, Walking, Drinking, Walking, Lying down}), which indicates a tendency to increase behaviors (feeding and locomotor activities) that guarantee the better welfare of the birds. The sequence of behaviors ‘Lying down’ followed by ‘Lying laterally’ occurred only in HS, which represents a stressful thermal environment for the bird. Using the pattern mining sequences approach, we were able to identify temporal relationships between thermal stress and broiler behavior, confirming the need for further studies on the use of temporal behavior sequences in environmental controllers.
... According to Talaty et al. (2010), broilers with poor walking ability (i.e. with GS scores of 4 and 5 on a scale of 0 to 5) had decreased mobility and trouble accessing feeders and water fountains, resulting in reduced feed intake and lower body weights. Behavioural responses such as Latency-to-lie have been employed to assess bird's leg health and overall wellbeing in broiler chicken (Weeks et al., 2003). Rapid growth rate in meat-type birds has been suggested to be a major cause of poor bone quality (Williams et al., 2004). ...
... The significant correlation between gait score and body weight in 8-12 weeks old Nicholas white poults agrees with the results of an earlier study conducted in commercial Pekin ducks which showed that body weight increased with age, but within an age, body weight decreased as walking ability or gait score became worse (Cara et al., 2015). The observed negative association between gait score and LTL agrees with earlier reports in broiler chickens that negative correlation exists between the two assessment methods (Weeks et al. 2003, Ayorinde et al., 2004, Webster et al., 2008. Caplen et al. (2014) reported that mobility impairments are closely related to lameness assessed using GS. ...
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Locomotion problems limit access to drinkers and feeders with a resultant effect on birds' survival and productivity. In this study, gait score (GS), latency-to-lie (LTL) and their association with body weight (BWT) and morphometric traits in light weight (Nigerian Local, NL) and heavy weight (Nicholas White, NW) strains of turkeys were evaluated. A total of two hundred day-old Nigerian local and Nicholas white poults were used for the study. Gait of poults were scored at 4, 8, 12 and 16 weeks of age using Kestin gait scoring system. Other parameters measured include latency-to-lie, body weight and morphometric traits at 4, 8, 12 and 16 weeks of age. The results showed that poults with normal walking ability (GS=0) in the light strain Nigerian local declined slightly from 88.4 percent at week 4 to 85.0 percent at week 16, while poults with normal walking ability (GS=0) in Nicholas white declined from 81.1 at week 4 to 16.4 percent at week 16, respectively. The GS of Nicholas White was higher (p<0.05) than that of NL at 8 and 16 weeks of age. The LTL values decreased (1310.1- 555.7 seconds) with the age of birds and were higher (p<0.05) in NL at 8, 12 and 16 weeks of age. Correlation (r =-0.256 to 0.278) between BWT and GS was significant (p<0.05) at weeks 8 and 12 in NW and at weeks 12 and 16 in NL. BWT was correlated (p<0.05) with body girth, keel length, femur length, shank diameter and Tibia Metatarsus in both genotypes. There was significant correlation (p<0.05) between LTL and GS (r= -0.36 to -0.87), BWT and LTL (r= -0.24 to 0.31), BWT and LM traits (r= 0.56 to 0.96) in both genotypes. It was concluded that GS and LTL are influenced by genotype and age of poults.
... RIR chickens under both intensive and free-range system had better indices of tibia robustness, whereas CobbSasso under these systems had intermediate values, and commercial fastgrowing Cobb-500 had poor RI under intensive and free-range systems. Dust-bathing and litter behaviour was higher in slow-growing birds than fast-growing ones and the values obtained (2.2 -5.98%) were higher compared with earlier literature (10.9%) (Weeks et al., 2000;Cornetto & Estevez, 2001;Hall, 2001). Dust-bathing is affected by various factors, of which dust material is important. ...
... Rural slow-growing chickens had lower bodyweight than fast-growing broilers ( Figure 2) and hence might have consequently had better behavioural repertoires than the other strains. The walking ability of the birds had been reported to be associated with body development, especially breast weight, which that may alter the centre of gravity of the birds (Weeks et al., 2000). Possibly, the fast-growing broilers were frustrated because of this imbalance. ...
Article
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The behaviour, welfare, and tibia characteristics of fast-and slow-growing chickens were evaluated in free-range and intensive production systems. A total of 720 birds of three strains were subjected to these systems after 21 days of rearing under the same intensive environment. Each treatment was replicated six times with 20 birds in each replicate. Data were collected for welfare aspects, including feather condition, footpad, hock joint and tonic immobility, behavioural features, especially feeding or foraging, sitting, walking, scratching, pecking and dust-bathing, and tibia characteristics, including weight, length, width, medullary canal diameter and robusticity index (4-8 weeks). Production system had significant effects on all welfare and behaviour aspects of the birds. However, tibia characteristics were not influenced by production system, except for medullary canal diameter. The strains differed significantly in welfare, tibia characteristics and behaviour. For example, the slow-growing strains had better feather condition, footpad and hock joint scores. Significant interactions of strain and production system were noted for all characteristics. It was recommended that Rhode Island Red chickens could be raised under either production system without compromising their welfare or causing adverse effects on leg health. ______________________________________________________________________________________
... Broiler chickens are typically housed in barren environments and at high stocking densities in order to minimize production cost, which has the potential to compromise broiler welfare [1,2,3,4] . In conventional housing systems, broilers spend approximately 80% of their time budget lying down, and a positive association between time spent lying down and lameness has been found, which negatively in uences broiler welfare [5] . Environmental enrichment (complexity) has a positive impact on animals' biological functioning and behavior [1,4,6,7,8,9,10] . ...
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Affective state can bias an animal’s judgement. Animals in positive affective states can interpret ambiguous cues more positively (“optimistically”) than animals in negative affective states. Thus, judgement bias tests can determine an animal’s affective state through their responses to ambiguous cues. We tested the effects of environmental complexity and stocking density on affective states of broiler chickens through a multimodal judgement bias test. Broilers were trained to approach reinforced locations signaled by one color and not to approach unreinforced locations signaled by a different color. Trained birds were tested for latencies to approach three ambiguous cues of intermediate color and location. Broilers discriminated between cues, with shorter latencies to approach ambiguous cues closest to the reinforced cue than cues closest to the unreinforced cue, validating the use of the test in this context. Broilers housed in high-complexity pens approached ambiguous cues faster than birds in low-complexity pens­–an optimistic judgement bias, suggesting the former were in a more positive affective state. Broilers from high-density pens tended to approach all cues faster than birds from low-density pens, possibly because resource competition in their home pen increased food motivation. Overall, our study suggests that environmental complexity improves broilers’ affective states, implying animal welfare benefits of environmental enrichment.
... The mean, CV, and individual pattern for the feeding duration per feeder visit were similar across all the feeder space treatments and bird ages. Previous research reported that the feeding duration per feeder visit could be affected by various leg conditions (Weeks et al., 2000), growth rate (Howie et al., 2009), and diet type (Li et al., 2020b). In this case, the broilers were fed with the same type of diets among the treatments and can walk to the feeder without leg issues based on observation; therefore, these may be the reasons for the similar performance of the DFV among the treatments. ...
Article
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Providing adequate feeder space in broiler production is important to ensure bird performance and well-being; however, the effect of feeder space on the behavioral responses of broilers remains unclear. The objective of this research was to investigate feeding behaviors of broilers provided with four feeder spaces, i.e. 2.3 cm/bird with one feeder (2.3FSO); and 2.3, 4.6, and 6.9 cm/bird with three feeders (2.3FST, 4.6FST, and 6.9FST, respectively). Sixteen identical pens, each with 45 broilers (Ross 708, mixed sex), were used to accommodate the four feeder space treatments. Feeding behaviors were continuously monitored from week 4 to week 8 using an ultra-high frequency radio frequency identification system. Number of feeder slots per feeder was 14 at 2.3FSO, 5 at 2.3FST, 9 at 4.6FST, and 14 at 6.9FST. The results show that the daily feeding time and number of feeder visits for broilers at 2.3FST were similar as those at 4.6FST and 6.9FST, but higher than those at 2.3FSO (P<0.01). The feeder utilization ratio was the highest at 2.3FST, indicating the feeder being used most efficiently under the treatment than under other treatments (P<0.01). Coefficient of variations (33.0-65.1%) of the feeding behavioral responses were similar among the treatments, suggesting similar group uniformity of feeding behaviors of individual broilers (P≥0.06). Feeders among all treatments may not be fully utilized, because for most of the time, less than six birds chose to eat simultaneously at a more-than-five-slot feeder in all treatments. Given the same feeder space, increasing feeder number can accommodate more birds to eat simultaneously. The outcomes of this study provide insights into improvement of feeder design and management for broiler production.
... Lame birds adapted their behaviour in a way that minimized movement while maintaining overall feed intake (Weeks et al., 2000). In the current experiment, the birds in the C+ve group stood less and rested more than all other treatment groups, suggesting that they experienced pain that was alleviated by treatment with ZONPs. ...
Article
The current experiment was designed to evaluate the effects of dietary supplementations of zinc oxide nanoparticles (ZONPs) on some behavioural, performance, welfare and histopathological changes in broilers exposed to multidrug resistant Staphylococcus aureus (MRSA)-induced footpad dermatitis(FPD). Eighty-four males Indian River (IR) broilers were randomly allotted to six different dietary treatments as follows C-ve, C+ve, 10, 20, 30 and 40 ppm ZONPs from 7- 49ds of age. At day 28, broilers (n = 70) were subcutaneously injected 0.5mL of saline containing 5.3 × 10⁷ cfu/ mL of S. aureus (MRSA) in each metatarsal foot pad. Control (non-infected) broilers were given 0.5 mL of saline (n = 14). Results clarified that non-infected birds and ZONPs fed birds had significantly higher standing and feeding activities and lower resting activities in comparison with the infected group. Also, the S. aureus infected group had significantly lower body weight gain (BWG) and higher feed conversion ratio (FCR) than the non-infected group. In addition, the non-infected birds and ZONPs groups had significantly lower object crossing and tonic immobility times (TI) and gait scores (GS) in comparison with the S. aureus group. Only ZONPs 30, 40 ppm and non-infected groups had significantly higher latency to lie time (LLT) and lower serum cortisol level in comparison with the S. aureus group. Moreover, there were significant changes in the gross lesion score and histopathological lesion between the different groups. In conclusion, the dietary supplementation of ZONPs can reduce S. aureus induced negative effects of FPD in broilers.
... Lame birds adapted their behaviour in a way that minimized movement while maintaining overall feed intake (Weeks et al., 2000). In the current experiment, the birds in the C+ve group stood less and rested more than all other treatment groups, suggesting that they experienced pain that was alleviated by treatment with ZONPs. ...
Article
The current experiment was designed to evaluate the effects of dietary supplementations of zinc oxide nanoparticles (ZONPs) on some behavioural, performance, welfare and histopathological changes in broilers exposed to multidrug resistant Staphylococcus aureus (MRSA)-induced footpad dermatitis(FPD). Eighty-four males Indian River (IR) broilers were randomly allotted to six different dietary treatments as follows C-ve, C+ve, 10, 20, 30 and 40 ppm ZONPs from 7- 49ds of age. At day 28, broilers (n = 70) were subcutaneously injected 0.5mL of saline containing 5.3 × 107 cfu/ mL of S. aureus (MRSA) in each metatarsal foot pad. Control (non-infected) broilers were given 0.5 mL of saline (n = 14). Results clarified that non-infected birds and ZONPs fed birds had significantly higher standing and feeding activities and lower resting activities in comparison with the infected group. Also, the S. aureus infected group had significantly lower body weight gain (BWG) and higher feed conversion ratio (FCR) than the non-infected group. In addition, the non-infected birds and ZONPs groups had significantly lower object crossing and tonic immobility times (TI) and gait scores (GS) in comparison with the S. aureus group. Only ZONPs 30, 40 ppm and non-infected groups had significantly higher latency to lie time (LLT) and lower serum cortisol level in comparison with the S. aureus group. Moreover, there were significant changes in the gross lesion score and histopathological lesion between the different groups. In conclusion, the dietary supplementation of ZONPs can reduce S. aureus induced negative effects of FPD in broilers.
... Rearing in good conditions of broilers is a good approach to decrease stress, pain, diseases, and to increase health, activity, and welfare. Modern broiler chickens are raised for rapid growth, and studies have indicated that they spend about 80% of their lifetime to rest (Weeks et al., 2000). However, combined with immobility and fast growth, it creates a risk factor for the evolution of lameness and pathologies associated with the locomotor system (Bradshaw et al., 2002) and is likely to result in less welfare due to pain for the chickens and commercial losses for the producer. ...
... Sans et al. (in press) observed more exploratory and panting behaviour in OS than CS houses during the summer and autumn in the same region in Brazil, which demonstrated difficulties in meeting bird behavioural needs in both barn types. The highly modified genetics of commercial strains has led chickens to spend from 76% to 86% of their time inactive, according to age and any locomotor problems (Weeks et al. 2000). The high level of inactivity is an important welfare problem, which may relate to other welfare problems, such as contact dermatitis and leg abnormalities (Bessei 2006). ...
Article
• The following trial compared broiler chicken welfare in closed-sided (CS) versus open-sided (OS) industrial house types during the winter season in the South of Brazil. • Ten flocks in each house type were evaluated as follows: a) bird health: contact dermatitis on the breast and abdominal areas (CDE), bird soiling (BSO), footpad dermatitis (FPD), hock burn (HBU), lameness (LAM), fractures (FRA), bruising (BRU), scratches (SCR), dead on arrival (DOA), and diseases (DIS); b) house environmental measurements: relative humidity (RHU), temperature (TEM), air velocity (AVE), illuminance (ILL), ammonia concentration (NH3), and carbon dioxide concentration (CO2), and c) bird behaviour and affective states: bird behaviour (BBE), touch test (TTE), and qualitative behaviour assessment (QBA). • Statistical analyses were based on regression models for CDE, BSO, FPD, HBU, LAM and generalised linear models for DOA, FRA, BRU, SCR, DIS. The Mann-Whitney test was used for RHU, TEM, AVE, ILL, NH3, CO2, and the t-test for TTE and LMO, with a specific regression model for BBE data and Principal Component Analysis for QBA. • According to odds ratio for worse scores for CS relative to OS, birds were less likely to have severe scores for CDE (P=0.040 and P=0.007), BSO (P=0.031, P=0.016, and P=0.038), and HBU (P=0.017), and had higher median values for AVE (2.3, 0.0-7.8 m s⁻¹ vs. 0.0, 0.0-4.3 m s⁻¹), lower NH3 concentration (9.0, 0.0-64.0 ppm vs. 12.0, 0.0-60.0 ppm) and TTE scores (98, 96-100 vs. 67, 25-100). Worse results were observed in CS houses for higher stocking density (13.8±0.2 birds/m² vs. 12.0±0.2 birds/m²), RHU (74.5, 50.7-99.9% vs 72.3, 47.4-99.9%), and TEM (23.9, 14.6-29.2ºC vs. 21.7, 12.9-30.1ºC), lower ILL (16.0, 1.0-60.0 lx vs. 161.0, 8.0-2380.0 lx), less drinking (P=0.007), more inactive behaviour (P<0.001) and lower positive emotions, according to QBA (P=0.028). • In the studied region and season, CS houses seemed to offer fewer welfare problems in terms of the health indicators; however, OS houses showed fewer behavioural restrictions and higher positive emotional states.
... These results suggest that increasing the stocking density resulted in a decreased space allowance, decreased feeding and drinking space, and increased competition between the birds, which lead to a significant reduction in ingestive behaviour. Similarly a range of authors (SAPRA et al., 1995;REITER and BESSEI, 2000;WEEKS et al., 2000;SANOTRO et al., 2002;SPINU et al., 2003;ZUPAN et al., 2005;ALBENTOSA et al., 2007;ABD EL-RAZEK and FOUAD, 2008) reported that increasing the stocking density of quail resulted in the quail spending less time feeding and drinking than quail housed at an optimum stocking density. These results are in disagreement with the findings of OLUKOSI et al. (2002), who reported that there was no significant difference in oral behaviour patterns between different space allowances. ...
... standing or sitting) adopted to 412 perform the behaviors changed. In addition to sitting while feeding, Weeks et al. (2000) to low representation in the current data set, this behavior was merged with sitting to the 416 behavioral category 'inactive' and therefore not analyzed separately. Furthermore, in a study 417 of broilers reared commercially to 6 weeks of age and then moved to furnished cages in an 418 experimental setting, Skinner-Noble and Teeter (2009) compared behavior of GS2 and GS3 419 birds and found the latter to rest more and stand less. ...
Article
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Impaired walking ability in terms of slight or definite defects is more common in broiler production than lameness that obviously hinders movement, but it has received limited scientific attention. This study aimed to compare behavior of conventional broilers with impaired walking ability (assessed as gait score (GS) 2) with those walking normally (GS0) and those with only a slight gait defect (GS1). Behavior in the home environment was registered and an analgesic intervention to quantify changes in time budgets indicating pain relief was applied. The study included 192 Ross 308 broilers. On day 27 of age, the birds were distributed as evenly as possible into birds of GS0 and GS2 of each sex based on obtained gait score. Following this, each experimental bird was housed with three companion birds. On days 30 and 32 of age, the behavior in the home pens was recorded. All experimental birds were injected with the NSAID carprofen on one of the two days and saline on the other. The statistical analyses used the GS scored on the day of recording as explanatory factor. Compared to GS0 birds, GS2 birds tended to be more inactive (mean (CI): 4193 (3971-4416) versus 4005 (3753-4257) s; P = 0.074), spent more time sitting while feeding (306 (266-353) versus 213 (180-251) s; P = 0.026), were less likely to perch (probability: 0.78 (0.69-0.85) versus 0.91 (0.85-0.95); P = 0.012), and spent less time performing comfort behavior (749 (689-814) s versus 875 (792-967) s; P = 0.043). Compared to GS1 birds, GS2 birds spent more time inactive (GS1: 4022 (3818-4225) s; P = 0.027), less time foraging (289 (253-329) versus 347 (309-388) s; P = 0.047), and were less likely to perch (GS1: 0.90 (0.86-0.93); P = 0.001). For some of these behavioral variables, administration of carprofen led to behavioral changes across the GSs, which may suggest that the behavioral expression of the broilers were limited by pain. These findings are of relevance to animal welfare, but the underlying causes are still not fully clarified.
... reaching 78.0% of the birds in CS houses during winter, which reveals a major welfare problem for birds in industrial intensive poultry systems, regardless of the kriging map results. Lameness promotes significant physiological challenge to birds by pain (EFSA, 2012;Granquist et al., 2019), changing their behaviour by keeping them more inactive and decreasing the number of visits to feeders (Weeks et al., 2000). Granquist et al. (2019) observed a correlation between lameness and the increased prevalence of hock burn and footpad dermatitis. ...
Article
The science of animal welfare is key to improving the life quality of billions of chickens, by supporting decisions through the assessment of environmental and animal-based indicators in different conditions. Our goal was to assess the variation of bird welfare within the same barn and whether this variation depends on barn type or season. We described and compared the in-barn heterogeneity of broiler chicken welfare in four closed-sided (CS) and 13 open-sided (OS) industrial poultry houses, during two different seasons (summer/autumn and winter). The measures were divided into two categories: 1) environmental indicators: relative humidity, temperature, air velocity, ammonia (NH3) and carbon dioxide (CO2) concentrations, and illuminance; 2) animal-based indicators: contact dermatitis on the breast and abdominal areas, bird soiling, footpad dermatitis, hock burn, and lameness. The results of assessments in 30 equidistant locations, covering the whole inside area of each barn, were organized into kriging maps. Linear regression and generalized models were fitted, considering predictor variables and the interaction effect between them; the Tukey test was used for the multiple comparisons of means. We used geostatistical modelling for continuous and discrete data for environmental and animal-based measurements, respectively. In-barn heterogeneity was observed for the prevalence of environmental and animal-based problems. There was a pattern for the spatial distribution, heading from the house centre to the West end of both house types, with worse results for three environmental indicators (higher temperature, and NH3 and CO2 concentrations) and three animal-based indicators (higher prevalence of hock burn, bird soiling and footpad dermatitis). In CS, illuminance was very restrictive (4.4 to 6.7 lx) when compared to OS houses (119.8 to 145.3 lx); in both house types the prevalence of lameness was high (50.9 to 78.0%), even though both illuminance and lameness prevalence were evenly distributed inside all houses. The kriging maps allowed for the identification of worse welfare problems in the West direction, which in CS means near exhaust fans and in OS houses the direction of positive-pressure mechanical ventilation by fans. Our results show that attention is needed for the variation of bird welfare conditions inside each barn, and allow for the adoption of strategies to spread best conditions throughout the internal barn area in both house designs. Principally, the original findings on in-barn bird welfare heterogeneity suggest the relevance of constant bird welfare monitoring in key locations within the barns, minimally for the indicators with known different in-barn spatial distributions.
... Current study included four behaviours which account for the major daily time budget of broilers. Weeks et al. (2000) compared the time spent of birds with different gait score in 16 behaviours. The results showed broilers spent 88% to 96% of time on the four behaviours we looked at in our study. ...
Article
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Understanding broiler behaviours provides important implications for animal well-being and farm management. The objectives of this study were to classify specific broiler behaviours by analysing data from wearable accelerometers using two machine learning models, K-Nearest Neighbour (KNN) and Support Vector Machine (SVM). Lightweight triaxial accelerometers were used to record accelerations of nine 7-week-old broilers at a sampling frequency of 40 Hz. A total of 261.6-min data were labelled for four behaviours – walking, resting, feeding and drinking. Instantaneous motion features including magnitude area, vector magnitude, movement variation, energy, and entropy were extracted and stored in a dataset which was then segmented by one of the six window lengths (1, 3, 5, 7, 10 and 20 s) with 50% overlap between consecutive windows. The mean, variation, SD, minimum and maximum of each instantaneous motion feature and two-way correlations of acceleration data were calculated within each window, yielding a total of 43 statistic features for training and testing of machine learning models. Performance of the models was evaluated using pure behaviour datasets (single behaviour type per dataset) and continuous behaviour datasets (continuous recording that involved multiple behaviour types per dataset). For pure behaviour datasets, both KNN and SVM models showed high sensitivities in classifying broiler resting (87% and 85%, respectively) and walking (99% and 99%, respectively). The accuracies of SVM were higher than KNN in differentiating feeding (88% and 75%, respectively) and drinking (83% and 62%, respectively) behaviours. Sliding window with 1-s length yielded the best performance for classifying continuous behaviour datasets. The performance of classification model generally improved as more birds were included for training. In conclusion, classification of specific broiler behaviours can be achieved by recording bird triaxial accelerations and analysing acceleration data through machine learning. Performances of different machine learning models differ in classifying specific broiler behaviours.
... Previous studies have investigated the link between GS and broiler welfare (Weeks et al., 2000;Skinner-Noble and Teeter, 2009;Norring et al., 2019) and it is generally agreed that GS ≥ 3 constitutes a welfare problem for the broilers. However, most experiments have compared higher gait scores (GS ≥ 3) with broilers assessed as GS0 (McGeown et al., 1999;Caplen et al., 2014;Hothersall et al., 2016;Aydin, 2017) and thus often excluded assessment of birds of GS2 as an intermediate score. ...
Article
Gait defects, assessed as gait score (GS), is a common welfare problem in broiler chicken production. The aim of this study was to examine whether birds with GS2 experience pain and poor locomotor ability compared to birds of lower GS. From day 0–27 of age, 600 Ross 308 birds were housed in simulated commercial conditions (stocking density 40 kg/m²). On day 27, all birds were gait scored and 192 birds (4 blocks of 48 birds) were selected as experimental birds based on gait score (GS0 or GS2). On day 28, a runway test with and without obstacles was performed to examine the locomotor ability of the birds. Approximately 3 h before testing, the experimental birds were injected with the NSAID carprofen (25 mg/kg s.c.) or saline (equivalent volume). A Conditioned Place Preference (CPP) test was conducted on day 38, after 4 days of conditioning to a chamber (70 × 70 cm; painted either green with vertical stripes or orange with horizontal stripes) after injection with carprofen or saline. The broilers were expected to show a preference for the place in which they experienced a positive emotional state as induced by the mitigation of pain by carprofen. In the runway test, GS0 birds reached the end of the runway with obstacles faster compared to GS2 birds (P = 0.04) and tended to be faster than GS1 birds (P = 0.08). No effect of carprofen was found on the behaviour in the runway and no effect of GS on the behaviour in the runway without obstacles. In the CPP test, there was no effect of GS or carprofen on chamber preference (P > 0.05). The results showed clear differences between birds of GS2 and lower GSs in terms of locomotor response in the runway, indicating that locomotor ability was compromised with increased GS. The results could not confirm whether these differences in locomotor ability are related to or due to increased pain with increased GS.
... A high WG and mean weight was observed with the inclusion of increasing levels of glucosamine sulfate, probably because of the positive results regarding locomotor problems of broiler chickens. N€ a€ as et al. (2009) provided evidence that broilers with lameness spend less time on standing activities because of chronic pain, which compromises welfare and results in low feed and water intake (Weeks et al., 2000). Sgavioli et al. (2017) and Santos et al. (2019) confirmed this hypothesis and concluded that chondroitin and glucosamine sulfates were effective in improving feed conversion and breeding viability owing to the positive results regarding bone and cartilaginous development of broilers. ...
Article
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This study aimed to assess the influence of glycosaminoglycan (chondroitin and glucosamine sulfates) supplementation in the diet on the performance and incidence of locomotor problems in broiler chickens. A completely randomized design was carried out in a 3 × 3 factorial scheme (3 levels of chondroitin sulfate −0, 0.05, and 0.10%; and 3 levels of glucosamine sulfate −0, 0.15, and 0.30%). Each treatment was composed of 6 replications of 30 broilers each. The performance of broilers (average weight, weight gain, feed intake, feed conversion, and productive viability) was assessed at 7, 21, 35, and 42 d of age, whereas the gait score, valgus and varus deviations, femoral degeneration, and tibial dyschondroplasia were assessed at 21 and 42 d of age. Increasing levels of glucosamine sulfate inclusion linearly increased the weight gain from 1 to 35 and from 1 to 42 d of age of broilers (P = 0.047 and P = 0.039, respectively), frequency of broilers with no femoral degeneration in the right and left femurs, and the proliferating cartilage area of proximal epiphysis at 42 d of age (P = 0.014, P < 0.0001, and P = 0.028, respectively). The increasing inclusion of chondroitin and glucosamine sulfates led to an increase in the frequency of broilers on the gait score scale 0 (P = 0.007 and P = 0.0001, respectively) and frequency of broilers with no valgus and varus deviations (P = 0.014 and P = 0.0002, respectively) also at 42 d of age. Thus, chondroitin and glucosamine sulfates can be used in the diet of broiler chickens to reduce their locomotor problems.
... Sans et al. (in press) observed more exploratory and panting behaviour in OS than CS houses during the summer and autumn in the same region in Brazil, which demonstrated difficulties in meeting bird behavioural needs in both barn types. The highly modified genetics of commercial strains has led chickens to spend from 76% to 86% of their time inactive, according to age and any locomotor problems (Weeks et al. 2000). The high level of inactivity is an important welfare problem, which may relate to other welfare problems, such as contact dermatitis and leg abnormalities (Bessei 2006). ...
Article
We compared closed- and open-sided industrial houses with respect to the welfare of broiler chickens in southern Brazil. Ten flocks from each design were evaluated and measures divided into the following categories: i) bird health: contact dermatitis on the breast and abdominal areas, bird soiling, foot-pad dermatitis, hock burn, lameness, fractures, bruising, scratches, dead on arrival, diseases; ii) environmental measurements: relative humidity, temperature, air velocity, ammonia (NH3), carbon dioxide (CO2), light intensity, litter moisture; iii) behaviour: bird behaviour, touch test; and iv) affective states: qualitative behaviour assessment. Closed-sided houses showed worse contact dermatitis on the breast and abdominal areas, lower exploratory behaviour prevalence, higher NH3 (11.2 [± 6.8] vs 7.5 [± 3.9] ppm) and CO2 (1,124.9 [± 561.5] vs 841.0 [± 158.0] ppm), lower light intensity (6.9 [± 6.3] vs 274.2 [± 241.9] lux), while open-sided houses had a higher prevalence for scratches and panting behaviour, and lower air velocity (2.1 [± 0.7] vs 1.1 [± 1.0] m s–1). Stocking densities of 13.9 (± 0.4) and 12.0 (± 0.3) per m2 for closed- and open-sided houses, respectively, likely influenced some results. All values shown are means (± SD). Even though open-sided houses presented fewer animal welfare restrictions (according to five indicators as opposed to three for closed-sided houses), both revealed important welfare problems, evidenced by poor environmental indicators, behavioural restrictions and injuries.
... Impaired locomotion has been linked to high growth rate, high body weight, infection, and housing conditions (e.g., light and feeding regime) in broilers (Bradshaw et al., 2002). Birds with impaired locomotion have trouble accessing feed and water (Weeks et al., 2000), performing motivated behaviors like dust bathing (Vestergaard and Sanotra, 1999), and likely with peck avoidance (Erasmus, 2018). Studies have reported that in broilers approximately 15-28% of the birds, and in turkeys, approximately 8-13% of the birds, examined had impaired locomotion (Kestin et al., 1992;Bassler et al., 2013;Sharafeldin et al., 2015;Vermette et al., 2016;Kittelsen et al., 2017). ...
Article
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Animal pose-estimation networks enable automated estimation of key body points in images or videos. This enables animal breeders to collect pose information repeatedly on a large number of animals. However, the success of pose-estimation networks depends in part on the availability of data to learn the representation of key body points. Especially with animals, data collection is not always easy, and data annotation is laborious and time-consuming. The available data is therefore often limited, but data from other species might be useful, either by itself or in combination with the target species. In this study, the across-species performance of animal pose-estimation networks and the performance of an animal pose-estimation network trained on multi-species data (turkeys and broilers) were investigated. Broilers and turkeys were video recorded during a walkway test representative of the situation in practice. Two single-species and one multi-species model were trained by using DeepLabCut and tested on two single-species test sets. Overall, the within-species models outperformed the multi-species model, and the models applied across species, as shown by a lower raw pixel error, normalized pixel error, and higher percentage of keypoints remaining (PKR). The multi-species model had slightly higher errors with a lower PKR than the within-species models but had less than half the number of annotated frames available from each species. Compared to the single-species broiler model, the multi-species model achieved lower errors for the head, left foot, and right knee keypoints, although with a lower PKR. Across species, keypoint predictions resulted in high errors and low to moderate PKRs and are unlikely to be of direct use for pose and gait assessments. A multi-species model may reduce annotation needs without a large impact on performance for pose assessment, however, with the recommendation to only be used if the species are comparable. If a single-species model exists it could be used as a pre-trained model for training a new model, and possibly require a limited amount of new data. Future studies should investigate the accuracy needed for pose and gait assessments and estimate genetic parameters for the new phenotypes before pose-estimation networks can be applied in practice.
... Elevated structures allow species-specific behaviours and the broilers have the possibility to choose several different seating positions [29]. These elements and activities may tackle the well-known problem in conventional chicken houses, i.e., the chickens are inactive for approximately 80% of their time [30,31] when not eating or drinking. Movement and choosing several different seating positions can help to distribute the load on the foot pads, while also help to increase muscle activity [32] and reduce lameness [24,33] and FPD [34]. ...
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The aim of this study is to evaluate the influence of environmental enrichment on the growth performance, litter and/or air quality as well as animal welfare indicators of broilers. Control groups (CG) and trial groups (TG) were housed under identical conditions during six fattening runs, with the TG having three types of environmental enrichment and a Farmer-Assistant System (FAS). A representative number of 50 birds were weighed and litter samples were taken at d 14, 21 and 28. Additionally, the same broilers were examined for foot pad dermatitis (FPD) on those days. The average bodyweight of the birds in the CG was significantly lower (1671 g) only at d 28 compared to TG (1704 g); at d 14, d 21 and d 33 at the slaughterhouse, no significant differences were observed. The dry matter content in the litter did not significantly differ between CG and TG. Birds housed in CG had significantly higher FPD scores at d 14 (1.24) and d 21 (2.19) compared to those housed in TG (0.73 and 1.52, respectively). No effects on air quality parameters, such as CO2 and NH3, were seen between the groups. Overall, our study shows no negative influences of environmental enrichment on growth performance, litter and air quality.
... Birds selected for fast growth (commercial broilers) suffer from leg disorders, organ failure and heart disease. At six weeks of age, broiler chickens have much difficulty supporting their abnormally heavy bodies as they spend 76 to 86 % of their time laying down (4). They may suffer from respiratory diseases, big liver and spleen disease and sudden death syndrome (5;6;7). ...
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Two hundred and sixteen unsexed 14 days-old Marshall broiler chicks were used in a 3×3 factorial experimental layout to test the effect of restricting feed intake of birds to 0%, 20% and 40% levels for 2, 4 and 6 weeks. The experiment lasted for 42 days. Data were collected on blood and serum profile, carcass characteristics, while the cost-benefit analysis was calculated. Data obtained were subjected to a 2-way analysis of variance. Results showed that duration and level of restriction had significant effect (P<0.05) on blood parameters except red blood cell while serum cholesterol values decreased significantly (P<0.05) with increasing level and duration of restriction. Abdominal fat decreased with increasing duration and level of restriction with birds on 40% level and 6 weeks duration of restriction having the lowest fat content (0.20%). As level and duration of feed restriction increased, feed cost/ kg reduced. Birds restricted at 40% level for 2, 4 and 6 weeks durations respectively had better cost benefit than birds restricted at 0 and 20% levels for 2, 4 and 6 weeks durations. It can be concluded that lower abdominal fat, cholesterol and better cost benefit was achieved in birds restricted at 40% for 6 weeks. The diet therefore produced lean meat at reduced cost which can be of advantage to the producer.
... However, the current facilities have low complexity, homogeneous rearing environment, and present several factors that can compromise broiler chicken welfare (Norring et al., 2016). According to Weeks et al. (2000), broiler chickens remain seated for approximately 86% of their lives, and such inactivity causes skeletal disorders in their legs, as well as lameness, and pod dermatitis -these conditions get worse as they age (Knowles et al., 2008). ...
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The inclusion of environmental enrichment in conventional broiler rearing can increase mobility, bone mass and muscle. This research aimed to evaluate the use of environmental enrichment in the rearing of broilers at different ages and its influence on performance, morphometry, yield and weight of the parts. It was used the completely randomized design in split-plot scheme, being the plots the treatments presence (T1) and absence (T2) of environmental enrichment and the subplots the broiler ages (1, 7, 14, 21, 28, 35 and 42 days), with 56 chicks in each treatment (T1 and T2). Data obtained were analyzed by the linear effect model of fixed effects and compared by Tukey’s test of means. The animals were raised in a controlled environment, divided into four boxes with dimensions: 1.5 × 1.0 × 0.7 m, containing rice straw bed. In T1 a ladder with a perch on top was used, distributed every 1.5 m2. Environmental enrichment used did not influence broiler’s zootechnical performance. Broilers’ morphometric properties, parts weight and body weight increased due to environmental enrichment and, improvement was observed in chicks rearing’s final phase. The environmental enrichment was beneficial for muscle and bone mass gain in the main commercial parts of the chicken carcass, in addition to reducing the allometric coefficient of the breasts in chickens.
... The subject was then given a score out of three categorical descriptors (0-2) from Webster et al. 93 . Score "0" indicated the subject was able to walk at least 1.5 m with no obvious impairment and a balanced gait; score "1" was given to subjects able to walk at least 1. 5 www.nature.com/scientificreports/ with a clear limp or awkward gait; and score "2" indicated that the subject was unable to walk 1.5 m, showing severe impairment with or without shuffling on the shanks or hocks with assistance of wings. ...
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Affective state can bias an animal’s judgement. Animals in positive affective states can interpret ambiguous cues more positively (“optimistically”) than animals in negative affective states. Thus, judgement bias tests can determine an animal’s affective state through their responses to ambiguous cues. We tested the effects of environmental complexity and stocking density on affective states of broiler chickens through a multimodal judgement bias test. Broilers were trained to approach reinforced locations signaled by one color and not to approach unreinforced locations signaled by a different color. Trained birds were tested for latencies to approach three ambiguous cues of intermediate color and location. Broilers discriminated between cues, with shorter latencies to approach ambiguous cues closest to the reinforced cue than cues closest to the unreinforced cue, validating the use of the test in this context. Broilers housed in high-complexity pens approached ambiguous cues faster than birds in low-complexity pens–an optimistic judgement bias, suggesting the former were in a more positive affective state. Broilers from high-density pens tended to approach all cues faster than birds from low-density pens, possibly because resource competition in their home pen increased food motivation. Overall, our study suggests that environmental complexity improves broilers’ affective states, implying animal welfare benefits of environmental enrichment.
... It is logical to conclude that lameness is painful (McGeown et al., 1999;N€ a€ as et al., 2009) and, consequently, stressful in broilers (Danbury et al., 2000;Weeks et al., 2000;Weimer et al., 2020). For example, Danbury and colleagues (2000) reported that, when given the choice, broilers with an impaired gait selected to consume feed supplemented with an analgesic (carprofen) more than broilers with a normal gait. ...
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Stress and lameness negatively affect the health, production, and welfare. Bacterial chondronecrosis with osteomyelitis (BCO) is a leading cause of stress and lameness in commercial broilers. External changes in skin temperature related to changes in blood flow can be detected with infrared thermography (IRT), offering a noninvasive tool to assess the health of animals. This study compared physiological and noninvasive measures of stress and lameness in clinically healthy and lame male broiler chickens between 25 and 56 d. Birds were raised in pens within separate environmental chambers with either litter flooring (sound) or wire flooring, with the latter established to induce BCO lameness (lame). Physiological and non-invasive measures of stress and lameness were collected: body weight, (BW), relative bursa weight, core body temperature, corticosterone (CORT) concentrations in serum and feathers, surface temperatures of the head (eye and beak) and legs (hock, shank, and foot) regions by infrared thermography (IRT), leg blood oxygen saturation (leg O2), and BCO lesion severity scores of tibial head necrosis (THN) and femoral head necrosis (FHN). Lame birds exhibited higher FHN and THN lesion severities, core body temperatures, and serum CORT (P < 0.05), but had lower BW, relative bursa weight, leg O2, and IRT surface temperatures of the beak, hock, shank, and foot compared with sound birds (P < 0.05). The difference in THN lesion severity between sound and lame birds decreased with age. Linear relationships between leg O2 with IRT leg surface temperatures were positive and negative between leg O2 with BCO lesion severity (P < 0.05). There were negative correlations between serum CORT with hock, shank and foot temperatures (P < 0.001), indicating that BCO is stressful. These present results indicate birds lame from BCO are stressed and have reduced oxygen saturation of blood in their legs and that IRT surface temperatures can be used as noninvasive indicators of stress and lameness in broilers.
... A inactividade-é un problema típico nas aves de cebo, especialmente en broilers e pavos, que teñen dificultades para andar (Weeks et al., 2000). Isto débese á intensa selección de animais con altos índices de crecemento e de conversión que xeraron estirpes aviarias moito menos activas. ...
... Dorsal cranial myopathy-a lesion in the cranial portion of the back of broiler chickens, in the anterior Latissimus dorsi muscle, which is responsible for supporting the abduction of the In the present study, the animals in the EE treatment exhibited higher frequencies of scores 0 (intact muscle, with no apparent macroscopic lesions) and 1 (muscle with superficial haemorrhage, paleness, and gelatinous surroundings) than those in the NEE group, which exhibited a higher frequency of score 2 (muscle with uni-or bilateral altered colour exhibiting necrosis and increased volume) (P = 0.0188). It is likely that the greater level of activity of the animals in the EE treatment, associated with the use of step platforms, may have strengthened their locomotive system, thus preventing the skeletal-biomechanical imbalance caused by exacerbated growth of the Pectoralis major muscle in modern chicken lineages [6,7]. The higher frequency of calmer birds in the EE treatment may also be associated with the reduced incidence of dorsal cranial myopathy since chickens with greater expression of fear to human approximation and touch tend to escape while flapping their wings. ...
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The present study aimed to assess the influence of adding straw bales, step platforms, and laser projectors as environmental enrichment resources on the behaviour and welfare indicators of broiler chickens ( Gallus gallus domesticus ). A sample of 4,000 day-old male Cobb® 500 birds was used. The experimental treatments consisted of No Environmental Enrichment (NEE)—similar to a conventional environment; and Environmental Enrichment (EE)—environment enriched with straw bales, step platforms, and laser projectors, with four replicates per treatment of 500 animals. Behavioural characteristics (ethological observation through cameras, grab test, and modified touch test) and animal welfare indicators (pododermatitis and dorsal cranial myopathy) were assessed. The birds submitted to the EE treatment exhibited greater exploratory activity and expression of behaviours associated with comfort and welfare, whereas those in the NEE group were less active. Locomotion and play fighting behaviour decreased and behaviours associated with comfort increased as age advanced. The frequencies of interaction with laser spots and birds lying around straw bales were the highest in the 1 st week (P<0.01). The behaviours of pecking at straw bales (P<0.0004), using the step platforms (P = 0.0001) and being on top of straw bales (P<0.0002) gradually increased. The chickens accessed the feeding troughs the most in the period of 0800 hours (P<0.0001) and expressed the highest frequencies of behaviours associated with comfort in the 1400 hours and 1700 hours periods. The birds in the EE group were calmer in face of human presence and touch and scored higher in animal welfare indicators. Adding straw bales, step platforms, and laser projectors increased locomotion, reduced expression of fear, and improved animal welfare indicators of broiler chickens.
... This is consistent with other studies and is suggested to be due to a decrease in the activity of broiler chickens with age [29][30][31]. This is presumably due to higher body weight and an increasing rate of lameness [32] and, therefore, discomfort or pain [33]. ...
Article
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Broiler chickens in Europe are usually raised in a barren environment. Elevated perforated platforms address this problem and can positively influence animal health and welfare. To evaluate the effect of an elevated perforated floor on the behavior of broiler chickens, one of two barns was equipped with a perforated flooring system under the food and water supply. The second barn was used as a control. In total, three fattening periods were observed, with 500 broiler chickens (Ross 308 breed) kept in each barn. To compare the behavior of the birds in these groups, cameras were installed in the two barns. The videos were analyzed by counting the number of birds and observing focal animals while recording their behavior. More animals were observed on the perforated floor than in the littered control area (p < 0.001), but focal animals spent less time on the perforated floor compared to the observed littered area in the control barn (p < 0.05). There were no differences in the length of the recorded behaviors between the treatments. These findings suggest that, in general, the elevated perforated floor is attractive for the animals. However, it does not promote one of the recorded behavior patterns. Our results show that an elevated perforated floor could be an option for structuring broiler barns.
... A possible explanation for this is that, regardless of the light source, the time spent resting (sitting) increased as broilers grew older, which is thought to be another consequence of increased body size and decreased mobility [4,26]. ...
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This study evaluated the behavioural response and weight of broiler birds at the 4th and 6th week of age when raised under incandescent (ICD) and compact fluorescent light (CFL). At 2 weeks of age, a total of 216 Arbor Acres birds were randomly allotted into 3 treatments: Control (no artificial light), ICD (60 watts, 800 lm) and CFL (40 watts, 2000 lm). Artificial lighting was provided from 8 p. m. to 4 a. m. daily. Data collected were subjected to One-way ANOVA using Minitab 17 through a general linear model (GLM) procedure and means were separated using Tukey’s test software. At 4 weeks of age, the presence of light significantly increased (P < 0.05) the weight, as well as the occurrence of feeding, drinking, sitting, standing, walking, running and jumping behaviour. ICD and CFL had similar effects on feeding and jumping behaviour. At 6 weeks of age, the presence of light had no significant effect (P > 0.05) on the frequency of drinking and jumping behaviour. However, the weight, the frequency of feeding, standing, walking and running behaviour increased (P < 0.05) under the two light sources compared to the control. Also, birds raised under CFL displayed a higher frequency (P < 0.05) of inactive/resting and locomotor behaviour compared to birds reared under ICD which had a higher frequency of drinking behaviour. From this study, the use of CFL throughout the production stages is encouraged in poultry facilities due to the resultant increase in the activity levels of broilers and the reduced energy cost.
... This rapid growth is associated with health and welfare problems, including leg health issues and cardiovascular disease (see EFSA, 2010;Hartcher & Lum, 2019), and genetic selection strategies are associated with reduced activity levels (McLean et al., 2002). Levels of activity often decline with age (Weeks et al., 2000), and this inactivity can further add to health problems. While there is much focus on bird genetics, low levels of behavioural activity may also reflect lack of appropriate stimulation within housed systems. ...
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The welfare status of an animal is dependent on its ability to cope and exist in harmony with its environment, such that good physical and psychological health is maintained. Improving animal welfare is an increasingly important aspect of livestock production systems due, in a large extent, to increased consumer concerns about animal production practices. Animal welfare is an integrated part of quality assurance programmes for sustainable animal production, considering that welfare, health, management, economy, consumer acceptance and environmental impact are interdependent. The major welfare concerns in the livestock industry in recent years relate to the rearing and management of dairy calves, the welfare of the dairy cow, effect of husbandry management procedures on the welfare of beef cattle, rearing of sows in gestation and farrowing crates, and the broiler (meat) chicken sector. The paper will focus on scientific research underpinning these welfare concerns, with a particular focus on research conducted on the island of Ireland.
... Many of the causes of lameness are associated with pain and birds with critically impaired motility are unable to reach drinkers and feeders. Poor welfare has a negative effect on the health and production parameters of birds and affects the quality of animal products (Kestin et al. 1992;Weeks et al. 2000;Bradshaw et al. 2002;Gocsik et al. 2017;Granquist et al. 2019). Annual economic losses due to leg problems in the USA in early 1990s were estimated at $80-120 million in the broiler industry and $32-40 million in the turkey industry (Sullivan 1994). ...
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Lameness or leg weakness is the main cause of poor poultry welfare and serious economic losses in meat-type poultry production worldwide. Disorders related to the legs are often associated with multifactorial aetiology which makes diagnosis and proper treatment difficult. Among the infectious agents, bacteria of genus Staphylococcus are one of the most common causes of bone infections in poultry and are some of the oldest bacterial infections described in poultry. Staphylococci readily infect bones and joints and are associated with bacterial chondronecrosis with osteomyelitis (BCO), spondylitis, arthritis, tendinitis, tenosynovitis, osteomyelitis, turkey osteomyelitis complex (TOC), bumblefoot, dyschondroplasia with osteomyelitis and amyloid arthropathy. Overall, 61 staphylococcal species have been described so far, and 56% of them (34/61) have been isolated from clinical cases in poultry. Although Staphylococcus aureus is the principal cause of poultry staphylococcosis, other Staphylococcus species, such as S. agnetis, S. cohnii, S. epidermidis, S. hyicus, S. simulans, have also been isolated from skeletal lesions. Antimicrobial treatment of staphylococcosis is usually ineffective due to the location and type of lesion, as well as the possible occurrence of multidrug-resistant strains. Increasing demand for antibiotic-free farming has contributed to the use of alternatives to antibiotics. Other prevention methods, such as better management strategies, early feed restriction or use of slow growing broilers should be implemented to avoid rapid growth rate, which is associated with locomotor problems. This review aims to summarise and address current knowledge on skeletal disorders associated with Staphylococcus spp. infection in poultry.
... Notoriously, the active nature of chickens is negatively related to the DWG and slaughter age. Previous studies reported that the FG genotype spent 79% of their time lying down between 39 and 49 days of age, and their walking activity (3.3% of the time) decreased with increasing age [23]. The plumage conditions and body lesions confirmed that the more static genotypes (M and CY) also exhibited the lowest scores. ...
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This study aimed to develop an adaptability score (AS) for chicken strains, which includes behavioral, plumage conditions, and body lesion indicators through a multifactorial approach. A total of 600 male chickens from 6 poultry genotypes—Ranger Classic (R1), Ranger Gold (R2), Rowan Ranger (R3), Hubbard Red JA (A), CY Gen 5 × JA87 (CY), and M22 × JA87 (M)—were reared under organic conditions, fed ad libitum, and individually weighed weekly to calculate the daily weight gain (DWG). The behavioral observations consisted of the explorative attitude (EA), recorded at 21 days, and the behavioral patterns (BPs) recorded the week before the slaughter. The AS was established by a principal component analysis, and the AS of these genotypes was compared. Moreover, the effect of DWG and genotype on the AS was evaluated by univariable and multivariable regression models. Although the DWG and genotype were strictly dependent, genotype was the most important factor affecting the AS. In fact, its effect was significant both in univariable (p < 0.001) and multivariable models (p < 0.001). Conversely, the DWG was significant only in the univariable and lost significance when the effect of genotype was introduced in the model.
... Inactive behaviour was not different between barn sides or across different age categories. According to some studies, this behaviour may be associated with increased bird age, walking ability deterioration, body weight, and fast growth rates [11,51,59]. Although our study did not test the birds' walking ability, the number of culls regarding leg problems suggests that this problem was prevalent, causing suffering and pain to the birds, as well as limiting their behavioural repertoire. ...
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We aimed to investigate what broiler chickens prefer when given free choice between a barn side with artificial lighting only as opposed to the other barn side with natural light through glass windows and artificial light. Eighty-five 1 day-old male Cobb 500 broiler chickens were divided into 10 pens; half of each pen area was provided with only artificial light (OAL) and the other half with natural and artificial light (NAL), and birds were free to move across sides. Environmental indicators and external conditions such as temperature, relative humidity, air velocity, ammonia and illuminance were monitored inside and outside the barn. Chickens’ preference was registered each three days, divided in categories: I (at 9, 12, and 15 days), II (at 18, 21, 24, and 27 days), and III (at 30, 33 and 36 days). The effect of the interaction between environmental indicators and week was statistically different only for illuminance. Chickens preferred NAL to OAL from 18 days onwards (II p < 0.001; III p = 0.016). Drinking (p = 0.034) and exploration or locomotion (p = 0.042) behaviours were more frequent, and “not visible” behaviours (p < 0.001) were less frequent, in NAL. Foraging was the only behaviour with an interaction effect between age category and light treatment, as birds during period II expressed this behaviour more frequently in NAL than OAL (p = 0.003). For our experimental conditions, the chickens preferred NAL from 18 days of age onwards, when the confounding effect of the heating light was removed, and their behavioural repertoire was also different according to each side of the barn and to their ages.
Article
Improving leg health will support broiler health and welfare. Known factors to improve leg health are: replacing inorganic by organic macro minerals in the diet, providing environmental enrichments and using slower-growing broilers. However, it remains unknown how fast- and slower-growing broilers respond to a combination of providing organic macro minerals and an elevated platform as enrichment with regard to leg health. Therefore, the aim of this study was to identify whether a combined treatment of organic macro minerals and a platform affected leg health, tibia characteristics, behavior and performance of fast- and slower-growing broilers in a semi-commercial setting. The experiment had a 2 × 2 factorial arrangement, with 12.800 fast-growing (Ross 308) and 12.800 slower-growing (Hubbard JA757) broilers that were randomly allocated to a control (i.e., inorganic macro minerals without enrichment) or adapted treatment (i.e., organic macro minerals and a platform). Broilers were housed in groups of 800 per pen (47.5m²), with 8 replicates per treatment (total of 32 pens). Performance was measured weekly and over the total rearing period. Behavior was observed via scan sampling at a target weight of 0.6 and 1.9kg for both breeds. Walking ability (gait score), footpad dermatitis and hock burn were assessed in 10 broilers per pen just prior to slaughter weight. Leg disorders and tibia characteristics were assessed in the same broilers at slaughter weight (2.3kg). Hardly any interaction effects between breed and treatment were found on leg health, tibia characteristics, behavior or performance, suggesting fast- and slower-growing broilers responded to the treatment similarly. The adapted treatment improved tibia characteristics, and increased locomotion and performance, but did not affect leg disorders, walking ability or contact dermatitis in both fast- and slower-growing broilers. The positive effects of the adapted treatment on tibia characteristics in both fast- and slower-growing broilers may improve leg health, although the current study did not confirm this for leg disorders, walking ability or contact dermatitis.
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Chicken meat is one of the main animal protein sources for humans and is nowadays the second most produced and consumed meat in the world. Since 1950s, broiler (meat-type) chickens have undergone radical phenotypic and genotypic changes as a result of an intense genetic selection for fast growth and better feed efficiency. Accompanied by better management conditions and better feed quality, this selection has provided several advantages, such as high amount of meat production in a short time, less environmental pollution and considerable financial benefits for producers. However, it has also caused downsides for broiler chickens, such as poor leg health, impaired locomotion and lameness. One of the main reasons for these downsides is an imbalance between high growth rate and immature bones, because the speed of bone development is unable to keep up with fast growth. Poor leg health causes serious welfare issues and considerable economic losses, since these chickens have difficulties accessing feed and water, suffer from pain, dehydration and starvation as results of high risk of leg bone fractures, developmental bone abnormalities and infectious and/or non-infectious leg disorders. The main focus of this thesis is on leg bone development, specifically tibia, since it is the major weight carrying and the most loaded and affected leg bone during the growth period. The aim of this thesis was to investigate different approaches to improve leg health of fast and slower-growing broiler chickens by (1) dietary factors on the broiler chickens or indirectly via the broiler breeders, (2) incubation conditions and (3) environmental enrichment. The General Introduction of this thesis first describes suboptimal leg health, bone abnormalities and leg disorders observed in broiler chickens and their welfare and economic consequences. Then continues with leg bone quality measurements, such as bone morphological, biophysical and mechanical characteristics. Lastly, gives information on potential approaches, which are investigated in this thesis to improve leg health in broiler chickens. Chapter 1 of this thesis describes effects of a combination of organic macro and trace minerals, fish oil and hydrolyzed collagen in the diet of fast-growing male broiler chickens on growth performance, tibia morphological, biophysical and mechanical characteristics (day 28, 35 and 42), leg disorders, locomotion and home pen behaviour. Results of this study showed that organic minerals in the diet positively affected tibia morphological, biophysical and mechanical characteristics and also growth performance, while hydrolyzed collagen in the diet did not affect tibia characteristics and fish oil in the diet negatively affected these characteristics. It can be concluded that bone development might need more available minerals in the diet of current fast-growing broiler chickens. Chapter 2 of this thesis describes effects of green LED light during incubation, the separate effects of macro minerals source and trace minerals source during rearing on growth performance, tibia morphological, biophysical and mechanical characteristics (day 42), leg disorders, locomotion and home pen behaviour of fast-growing male broiler chickens. Results of this study showed that green LED light during incubation did not influence any of the tibia characteristics. Organic macro minerals positively affected tibia characteristics compared to inorganic minerals and trace mineral source did not affect these characteristics. It can be concluded that despite green light during incubation have been shown to positively affect growth performance in this study, it did not affect tibia characteristics. The source of macro minerals in the diet of broiler chickens seems to play a major role in bone development, rather than the source of trace minerals. Chapter 3 of this thesis describes effects of a combination of organic macro and trace minerals in the diet of fast and slower-growing broiler breeders on the amount of minerals in egg and hatchling, growth performance, tibia morphological, biophysical and mechanical characteristics (at similar body weights), leg disorders and home pen behaviour of their male offspring broiler chickens. Results of this study showed that mineral concentration in eggs and hatchlings were hardly influenced, but almost all tibia morphological, biophysical and mechanical characteristics of slower-growing offspring broilers were positively affected, whereas this effect was hardly seen in fast-growing chickens. It can be concluded that trans-generational mineral availability in offspring appears to play a role via other mechanisms than via absolute mineral concentrations in the egg and the source of minerals in slower-growing breeders’ diet appears to be more effective on bone development of their offspring than in fast-growing chickens, which might be related to time available for bone development. Chapter 4 of this thesis describes effects of eggshell temperature pattern in week 2 (37.8°C or 38.9°C) and week 3 (36.7°C and 37.8°C) of incubation of fast-growing male broiler chickens on tibia morphological, biophysical and mechanical characteristics (day 41 or 42), leg disorders and locomotion. Results of this study showed that a temperature of 38.9°C during the second week of incubation improved tibia characteristics of fast-growing broiler chickens. Incubation temperature in the third week appears to interact with the incubation temperature in the second week, resulting in a most advanced tibia development after incubation at 38.9°C in week 2, followed by 37.8°C in week 3 of incubation. It can be concluded that a 1.1°C higher EST than normal in week 2 of incubation appears to stimulate tibia morphological, biophysical and mechanical characteristics of broiler chickens. However, a 1.1°C lower EST in week 3 of incubation appears to have negative effects on tibia characteristics. Chapter 5 of this thesis describes effects of pen enrichment consisting of ramps, platforms, perches, large distance between feed and water and live Black Soldier fly larvae in the moss-peat dust bathing area on growth performance, tibia morphological, biophysical and mechanical characteristics (at similar body weights), leg disorders, locomotion and home pen behaviour of fast and slower-growing male broiler chickens. Results of this study showed that pen enrichment positively affected tibia biophysical characteristics in both fast and slower-growing chickens, while no effect was found on tibia morphological and mechanical characteristics. It can be concluded that pen enrichment can stimulate pathways involved in ossification and mineralization, rather than anatomical and physical bone properties. The General Discussion of this thesis summarizes the objectives and main findings from five experimental chapters and discusses how investigated approaches individually or together give insight in and improve our understanding of leg health of broiler chickens. This chapter ends with main conclusions and future research opportunities. The main conclusions of this thesis are: (1) Replacement of a combination of inorganic macro and trace minerals by their organic varieties in the diet of fast-growing broiler chickens positively affected growth performance and tibia characteristics. (2) Replacement of a combination of macro and trace minerals by their organic varieties in the diet of fast and slower-growing broiler breeders resulted in stimulated growth performance and tibia characteristics in slower-growing offspring broilers, while no effect was observed in fast-growing offspring broilers. (3) Trans-generational mineral availability in offspring broilers appears to play a role via other mechanisms than via absolute mineral concentrations in the egg, since mineral concentrations in eggs and hatchlings were not affected by mineral source. (4) Replacement of inorganic macro minerals in the diet of fast-growing broiler chickens by their organic varieties seems to be more effective than organic trace minerals on tibia characteristics. (5) Green LED light during incubation resulted in stimulated body weight gain, but no effect was found on bone development of broiler chickens. (6) An eggshell temperature of 38.9°C during the second week of incubation was more effective on tibia characteristics of fast-growing broiler chickens compared to an eggshell temperature of 37.8°C. An eggshell temperature of 38.9°C in second week, followed by 37.8°C in third week resulted in the most advanced tibia characteristics, while a 1.1°C lower EST in week 3 of incubation appears to have negative effects on tibia characteristics. (7) Pen enrichment positively affected tibia biophysical characteristics of both slower and fast-growing chickens, while no effect was found on tibia morphological and mechanical characteristics. Pen enrichment also resulted in lower body weight gain in both fast and slower-growing chickens, potentially due to higher activity and use of metabolic energy or lower feed intake. (8) It appears that tibia biophysical characteristics seem to give better response to source of the mineral both in broiler and broiler breeder diets, eggshell temperature during incubation and pen enrichment compared to morphological and mechanical characteristics, (9) The relationship between tibia development and leg abnormalities and disorders remained unclear due to very low incidence of leg abnormalities and disorders.
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This experiment evaluated the effect of light manipulation on the behavior and welfare of broilers using 280-day-old Arbor-Acre chicks, which were weighed and assigned to 7 treatments having 4 replicates and 10 birds per replicate. The light treatments were as follows: white light (WH), blue light (BL), green (GR), blue light switched to green light at 14 days (2BG), green light switched to blue at 14 days (2GB), blue light switched to green light at 28 days (4BG), and green light switched to blue light at 28 days (4GB). Feeding, drinking, resting, standing, walking, foraging and preening behaviors were observed using the scan sampling method. Behavior and welfare parameters such as footpad dermatitis and hock burn were evaluated and analyzed in a Completely Randomized Design. The results showed that feeding behavior of birds of BL, 2BG, and 2GB treatment groups was significantly higher (P < 0.05) than those of WH and GR at the starter phase. At the finisher phase, resting behavior of birds of 4GB was similar to those of 2GB but higher than those of the other treatments. It was concluded that switching of light from green to blue (4GB) at four weeks of age fostered ideal behavior and stimulated growth in broilers but had no effect on welfare parameters.
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The welfare of broilers is strongly dependent on the litter material because they spend their life in contact with it. The purpose of this study was to determine the effects of alternative litter materials on broiler behaviour. Two hundred eighty-eight 1-day old male broiler chicks were used. Chicks were placed in pens each having different litter material (Wood shavings (WS), paper waste sludge (PWS), sepiolite (S), the mix of 25% paper waste sludge & 75% sepiolite (25PWS+75 S), the mix of 50% paper waste sludge & 50% sepiolite (50PWS+50 S) and the mix of 75% paper waste sludge & 25% sepiolite (75PWS+25 S)). Broilers in the pens were recorded with a camera on the same day in a week during 6 weeks’ trial. When total behaviour was assessed from 1 to 41 days of age, the percentage of sitting behaviour was the highest in the WS group and the percentage of resting behaviour was the lowest in the groups of S and WS. It can be suggested that PWS, which is a waste product, does not have a negative effect on natural behaviour and welfare of broilers and it can be used alone or mixed with S as a litter material.
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The objective is to evaluate different bedding materials, including dehydrated grass, on performance and carcass yield and verify the physicochemical and microbiological characteristics of materials. The completely randomized experiment comprised 1,080 chicks in a 3 × 2 factorial design with three levels of dehydrated grass (0%, 25%, and 50%) and two bedding materials (rice husks and shavings). Total microorganism count and physicochemical characteristics, surface temperature of birds, and performance of birds were analyzed up to 42 days of age, when birds were slaughtered, and carcass yield was evaluated. The inclusion of grass showed a higher microbiological count after 1 day, stabilizing with materials after 28 days. The inclusion of 50% of dehydrated grass resulted in a higher surface bed temperature at 42 days. Inclusions above 25% of grass have a lower density and a greater water retention capacity, pH, moisture, and total nitrogen, in addition to a lower FDA in its structure. The highest ammonia emissions occurred with the inclusion of 25% of grass. The inclusion of dehydrated grass did not affect performance and carcass yield, favoring feed conversion at the initial stages. The inclusion of grass can replace up to 25% of shavings without harming physicochemical parameters of materials and birds' performance.
Article
1. This experiment determined the effect of increasing mobility in broiler chickens by placing barrier perches between feeder-drinker. In addition, the limitation of early weight gain by dietary energy and protein dilution on some welfare parameters, tibiotarsus measurements, fear and mobility level was examined. 2. A total of 504 male, one-day-old broiler chickens (Ross 308) were randomly allocated to four treatments with three replicate pens per treatment and 42 broiler chickens per pen as a 2 x 2 factorial arrangement. Treatments included feeding the basal control diet between 0-42 days or a diet diluted by 10% energy and 20% crude protein fed between 0-21 d, with the control diet fed between 22-42 d. The second factor was the presence or absence of barrier perches. All treatments were allocated as a completely randomised design. Welfare parameters (foot pad dermatitis, hock burn, gait score, feather score, breast blister), tibiotarsus measurements (bone mineral content, bone mineral density, fluctuating asymmetry and relative fluctuating asymmetry), tonic immobility and mobility level were recorded. 3. Results showed that access to a barrier perch and the diluted diet increased the mobility in broiler chickens. However, access to a barrier perch had no significant effect on tibiotarsus and welfare parameters. Broiler chickens had better gait scores (P<0.05) and lower foot pad dermatitis incidence (P<0.01) in groups fed the diluted diet. The diluted diet had no significant effect on bone mineral density but reduced the tibiotarsus bone mineral content (P<0.05). 4. In conclusion, the diluted diet provided positive effects in terms of leg health due to weight gain limitations in the early period, thus improving broiler chicken welfare.
Article
The study examined the distribution of Cobb 700 broiler chickens in large (1.524 m x 6.096 m) pens under commercial conditions with two nipple waterer lines and a single feeder. The light intensity in the house was 4 lx provided by LED lighting but with supplementary lighting along the feeder line. There was a gradation of light intensity from 100 lx at bird level by the feeders to 4 lx at the edge of the pen. In addition, a limited time budget was estimated. A video system was employed to record the number of birds eating, drinking, standing close (within 30 cm) to the feeder line, standing close (within 30 cm) to the nipple waterers, sitting close to the feeder line and sitting close to the nipple waterers. Numbers were determined by direct observation. The number of birds that were neither close to the feeders nor nipple waterers was calculated by difference [total birds minus number of birds close to feeder plus those close to waterers). Birds congregated close to the feeder: eating or standing or sitting. However, 56% were situated neither close to the lit feeder line or the nipple waterers. The percentage of the broiler chickens that were feeding and drinking was 12.8 and 8.2%, respectively. There were shifts in bird behavior during the day with more broiler chickens eating and drinking during the first hour of the photophase and fewer birds eating increasing age.
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Selection for rapid growth has produced heavier, more efficient broiler chickens, but has also introduced health and welfare issues, which may cause or be caused by inactivity. Rapid growth may also limit the performance of motivated behaviors, whereas the provision of enrichment may increase these behaviors and general activity. This study aimed to evaluate the inactivity, behavior, and enrichment use of 2 fast- (CONV) and 12 slower-growing broiler strains [categorized as fastest (FAST), moderate (MOD) and slowest slow (SLOW), based on their growth rates]. To evaluate inactivity, one male and one female from 153 pens were outfitted with omni-directional accelerometers from day 21 until processing (14-24 birds/strain from 8-12 pens/strain). Additionally, to supplement inactivity data, five-minute continuous behavioral observations of four focal birds per pen (2 males, 2 females) were conducted on days 26, 42, and 56 (72-148 observations of 8-12 pens/strain) to quantify the duration and frequency of various behaviors; at the same time, 5-11 instantaneous scan samples were also performed for pen-based enrichment use. Inactivity peaked at 78-80% of the day for all strains; however, those with slower growth rates reached these levels at older ages. Compared to slower-growing strains at the same age, faster-growing strains were more inactive, spent more time sitting and feeding, spent less time standing and walking, and used enrichments less; these differences mostly occurred at younger ages. Generally, at the same age, strains with similar growth rates (within the same category) behaved similarly, with only a few exceptions. Results suggest that not all strains identified as 'slow-growing' broilers behave differently from fast-growing broilers, nor do they all behave similarly to each other. As such, results suggest that improved broiler welfare, particularly with respect to reduced inactivity, the performance of a wider range of normal, motivated behaviors, and/or increased enrichment use, is related to the broiler strain's specific growth rate.
Article
Broiler chickens are prone to a range of complex health and welfare issues. To support informed selection of welfare traits whilst minimising impact on production efficiency and to address a major gap in understanding, we systematically explored associations between health and behavioural indicators of broiler welfare. One conventional (CNV, n = 350) and two slow-growing broiler breeds (SGH and SGN, respectively n = 400) were reared from hatch in pens of 50 birds. Birds were assessed for health (gait, plumage cover and dirtiness, pododermatitis, hockburn, and leg deviations) at 2.2 kg liveweight according to the Royal Society for the Prevention of Cruelty to Animals Broiler Breed Welfare Assessment Protocol. Behaviour and resource-use of 10% of birds per pen, on days 29 (all breeds) and 43 (SGH and SGN), was (i) scan sampled every 60 min between three to six and between twelve to fifteen hours after photoperiod onset; and (ii) continuously sampled sequentially from focal birds for 3 min each in a random order, during 15 min observation periods at three and twelve hours after photoperiod onset. Binary logistic generalized linear models were used, to assess respective associations between pen prevalence of each health outcome and (i) pen mean percentage scans of behaviour, and (ii) pen mean frequency and duration per 3 min focal observation of behaviour. Better growth rate and feed conversion but poorer health outcomes (mortality, gait, pododermatitis, feather cover) were more prevalent in CNV. Strong associations between behaviour and several heath indicators revealed, (i) increases in side-lying inactive, sitting inactive, and use of the litter relative to other resources, as primary and general indicators of poorer health, and (ii) increases in standing inactive, perch use, walking, Comfort, High Energy and Exploratory behaviour as primary and general indicators of better health. Of these, changes in side-lying, standing inactive, walking, Comfort and High Energy behaviour were particularly sensitive to small differences in health outcomes important for breed acceptance in high-welfare schemes. Crucially these behavioural measures additionally represent motivational and affective aspects of welfare not captured by health measures and allow opportunity for earlier intervention. Thus, to provide a comprehensive assessment of broiler experience, behaviour should be incorporated into broiler welfare assessments.
Article
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This experiment was conducted to investigate the effects of different levels of artichoke and onion on performance, blood metabolites and strength of tibia and femur bones of broilers. 520 one-day-old commercial 308 chicks were randomly assigned to five treatments and four replications (26 chicks per replication) from 1 to 42 days of age. Experimental treatments included control diet and control diet plus 1.5% artichoke, 3% artichoke, 1.5% onion and 3% onion. At the end of the experiment, one male bird was selected from each replicate and slaughtered to assess bone strength indicators. The results of data analysis showed that adding onions increased feed intake and artichokes decreased feed intake (P <0.05). Blood glucose levels decreased in onion-containing treatments and increased in treatments containing artichokes (P <0.05). Percentage of red blood cells increased in onion-containing treatments (P <0.05). The highest resistance of tibia and femur bones of broilers was related to artichoke-receiving chicks (P <0.05). Adding onions significantly increased the percentage of bone ash in the tibia and femur (P <0.05). The use of artichokes and onions significantly improved bone strength in broilers. Keywords: Artichokes, bone strength, broiler, blood indicators, onions.
Article
This trial was planned to study the impact of dietary 25-hydroxyvitamin D (25-OH-D3) and ultraviolet light on some economical characteristics of broiler chicks (e.g., body weight, feed consumption, feed conversion ratio, bone measurements, and behavioral aspects). A total of 360 one-day-old chicks were randomly divided into four treatments (6 pens/treatment with 15 birds/pen). The experiment was laid in a 2 × 2 factorial design. Two light sources; Light-emitting diode (LED) or ultraviolet light B (UVB) and two 25-OH-D3 levels (0 level as control and 300 g/ton). The distribution of treatments was as follows: Treatment 1 (LED with 300 g/ton 25-OH-D3); Treatment 2 (LED with control diet); Treatment 3 (UVB with 25-OH-D3); Treatment 4 (UVB with control diet). The main results revealed that using UVB lamps had a positive effect on body weight at the marketing age compared to the LED group (1.985 vs 1.939). Regardless of the light source, adding 25-OH-D3 to the ration had a positive effect on body weight, especially at 28 and 35 days of age. Regarding cumulative feed intake, both T2 and T3 groups respectively consumed more feed compared to others, the highly significant difference was observed among them. Apart from diet impact, LED birds consumed slightly more feed compared to UVB birds. Both T3 and T4 groups recorded the lowest and significant figures of H/L ratio compared to the rest groups. It is interested to note that UVB birds had a lower H/L ratio compared to LED ones. According to the current findings, broilers reared under UVB light had lower stress susceptibility and fear responses. In general, results obtained revealed that there was an added value and synergetic actions when using UVB light and vitamin 25-OH-D3 in diets for most studied traits.
Article
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The feeding patterns of young broilers were compared with those of young layers to see if any differences might explain the faster growth rate of broilers. During 5 d of observation, the broilers ate almost twice as much as the layers and gained twice as much weight. However, the broilers also converted their food more efficiently and it was thought that this accounted for their faster growth rate. Since there was no difference in the ability of the two strains to digest their food, and since any differences in basal metabolic rate between the strains were likely to be small, it was suggested that the layer strain probably expended more energy on various behavioural responses. The broilers spent half as much time feeding as the layers but ate more meals which were larger and of shorter duration than those of the layers. Although both strains showed the same daily pattern of food consumption, their patterns of feeding activity differed markedly and in general feeding activity bore little relation to food intake.
Article
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A method for measuring the prevalence of leg weakness by assessing the walking ability of broilers was developed. Walking ability was divided into six categories, from completely normal to immobile. The method was found to give consistent results when performed by the same people. In a survey of commercial, intensively reared broilers, 90 per cent had a detectable gait abnormality and 26 per cent suffered an abnormality of sufficient severity for their welfare to be considered compromised. The prevalence of leg weakness in free range broilers, and three commercial breeds of broilers was determined. The results indicated that genetic factors were an important cause of leg weakness in broilers and also identified a possible relationship between liveweight and leg weakness.
Article
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The influence of two light intensity treatments, 180 and 6 lx, on behavior and performance of broiler chickens was examined in two experiments. The first experiment tested male chickens reared to 9 wk of age and the second experiment tested both sexes reared separately to 6 wk. Behavioral data were collected by scan sampling of behavior recorded on video tape. Standing, walking, and total activity were higher under the 180 lx than the 6-lx treatment (P<.01), whereas feeding and drinking were not significantly affected by light intensity. Body weight, feed and water consumption, and feed conversion were unaffected by light intensity. Incidence of leg disorders at 6 wk and the percentage of bruised carcasses at 64 days were significantly lower under the higher light intensity treatment in the first experiment, as was mortality to 3 and 6 wk in the second experiment. No significant light intensity × sex interactions were detected. Results did not support the hypothesis that brighter lighting reduces performance due to increased chicken activity. Use of brighter lighting had no adverse effects on performance and there was some evidence that it may have a beneficial effect on welfare by reducing bruising.
Article
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Continuous light with 1 h of darkness at midnight is a common photoperiod for raising meat-type fowl. The logic behind the 1 h of darkness, usually provided between midnight and 0100 h, is to acclimate the birds to darkness in the event of a power failure. Increasing evidence from several research laboratories indicates that lighting regimens other than continuous light, such as intermittent or step-up lighting, can lower the incidence of leg abnormalities in meat-type fowl. Some evidence suggests that increased exercise contributes in part to the reduction in lameness due to lighting. Management can influence the incidence of leg and foot problems via effects on rate of gain, flooring systems, and litter moisture. Rapid weight gains have been correlated with tibial dyschondroplasia (TD), although more evidence is needed to determine whether other types of leg deformities, such as long bone distortion, are related to rapid growth rates. Using low intensity X-ray imaging (hand-held lixiscope), live breeders with TD lesions can be identified and the incidence of TD can be reduced in breeder flocks through genetic selection. In addition, turkeys can be selected for wider shanks to improve walking ability. Slippery surfaces should be avoided to prevent spraddled legs. With the exception of TD, broilers reared in cages have more leg deformities than floor-reared birds. Dry litter conditions can help prevent foot pad dermatitis caused by Staphylococcus aureus and other bacteria.
Article
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Over the last 40 yr, genetic selection for rapid growth and improved feed efficiency has been very effective in meat-type poultry. Combined with changes in the feed that have increased both the nutritional and physical density to encourage a high nutrient intake, growth rate has more than doubled. The effect of genetic selection for high muscle to bone ratio and high calorie intake of a ration that supplies all nutritional requirements causes significant mortality from cardiovascular disease. In the chicken, sudden death syndrome (flip-over) and pulmonary hypertension syndrome resulting in ascites are the most important. Ruptured aorta, spontaneous turkey cardiomyopathy (round heart), and cardiomyopathy causing sudden death produce high mortality in turkeys. Rapid growth induced by high nutrient intake alone can cause severe lameness, bone defects, and deformity, as these problems are seen in animals that have not been selected for rapid growth: dogs, horses, pigs, ratites and wild birds kept in zoologic gardens. In meat-type poultry, growth-related disease can be reduced or eliminated by reducing feed intake without affecting final body weight. Rapid growth alone may not be the pathogenic mechanism that results in cardiovascular or musculoskeletal defects. Metabolic imbalance induced by high nutrient intake may cause some of the conditions. These metabolic problems might be corrected without reducing growth rate.
Article
Lame and sound broilers, selected from commercial flocks, were trained to discriminate between different coloured feeds, one of which contained carprofen. The two feeds were then offered simultaneously and the birds were allowed to select their own diet from the two feeds. In an initial study to assess the most appropriate concentration of drug, the plasma concentrations of carprofen were linearly related to the birds' dietary intake. The walking ability of lame birds was also significantly improved in a dose-dependent manner and lame birds tended to consume more analgesic than sound birds. In a second study, in which only one concentration of analgesic was used, lame birds selected significantly more drugged feed than sound birds, and that as the severity of the lameness increased, lame birds consumed a significantly higher proportion of the drugged feed.
Article
There has been a long and continuing interest among poultry breeders and scientists in relationships of domestic fowl with their jungle fowl ancestor. Recent commercial practices in poultry breeding have greatly changed and improved the meat and egg stocks available for the production of food. There is concern, however, that artificial selection for traits of economic importance has caused a narrowing of the genetic base and subsequent reduction in genetic variability. Because continued progress in the achievement of increased growth or egg production depends heavily on genetic variability, its present status is of interest. Current techniques in molecular biology allow estimations to be made of genetic distance among populations. This paper reviews DNA fingerprinting in poultry using results from this technique to survey genetic diversity among jungle fowl, domestic fowl representative of stocks from several decades ago and today's commercial broilers and layers. The genetic distance between wild jungle fowl and layers has been found to be similar to that between wild jungle fowl and broilers. Within the two types of modern commercial fowl there is less genetic diversity among broiler than layer stocks.
Article
A study of the way in which semi-wild junglefowl allocate their time between different activities showed that in 60% of all minutes during the active part of the day, hens were seen to be ground pecking and in 34%, ground scratching. The fact that such a high proportion of time was spent in foraging activities is discussed in relation to the welfare of domestic fowl unable to perform such activities.
Article
Resting behaviour as well as other maintenance behaviours were studied in a group of Jungle Fowl (10 ♀♀, 1 ♂) and in a group of a medium hybrid commercial laying strain (9 ♀♀, 1 ♂). Observations were carried out under spacious and varied housing conditions. Both groups were observed for seven 24-h periods. Sleeping and dozing are defined and described and 24-h patterns of rest and other maintenance behaviours are shown. Results and differences between groups are discussed.
Article
Seven major types of sampling for observational studies of social behavior have been found in the literature. These methods differ considerably in their suitability for providing unbiased data of various kinds. Below is a summary of the major recommended uses of each technique: In this paper, I have tried to point out the major strengths and weaknesses of each sampling method. Some methods are intrinsically biased with respect to many variables, others to fewer. In choosing a sampling method the main question is whether the procedure results in a biased sample of the variables under study. A method can produce a biased sample directly, as a result of intrinsic bias with respect to a study variable, or secondarily due to some degree of dependence (correlation) between the study variable and a directly-biased variable. In order to choose a sampling technique, the observer needs to consider carefully the characteristics of behavior and social interactions that are relevant to the study population and the research questions at hand. In most studies one will not have adequate empirical knowledge of the dependencies between relevant variables. Under the circumstances, the observer should avoid intrinsic biases to whatever extent possible, in particular those that direcly affect the variables under study. Finally, it will often be possible to use more than one sampling method in a study. Such samples can be taken successively or, under favorable conditions, even concurrently. For example, we have found it possible to take Instantaneous Samples of the identities and distances of nearest neighbors of a focal individual at five or ten minute intervals during Focal-Animal (behavior) Samples on that individual. Often during Focal-Animal Sampling one can also record All Occurrences of Some Behaviors, for the whole social group, for categories of conspicuous behavior, such as predation, intergroup contact, drinking, and so on. The extent to which concurrent multiple sampling is feasible will depend very much on the behavior categories and rate of occurrence, the observational conditions, etc. Where feasible, such multiple sampling can greatly aid in the efficient use of research time.
Article
The behaviour of broilers reared at pasture from 4 to 12 weeks of age on a low density diet supplied either indoors or outdoors, was compared with that of birds reared inside on deep litter. This single study found few differences in behaviour. Activity levels of birds outside were initially greater, but from six weeks of age lying increased to comparable levels in all groups.Surprisingly little use was made of the extra space and facilities such as perches at pasture. It is proposed that the main reason for this was leg weakness as 80 per cent of the birds had a detectable gait abnormality at seven weeks of age. There was no evidence of reduced motivation to extend the behavioural repertoire, as, for example, ground pecking remained at significantly higher levels in the outdoor groups because it could also be performed from a lying posture.
Article
1. Observations were made for 1‐h periods on 19 birds aged from 27 to 50 d in a commercial meat chicken flock. Data were collected on the frequency, the total proportion of time spent in different behaviour patterns, and sequencing of behaviour.2. Sixty‐four percent of time was spent lying. Individuals engaged in up to 41 separate lying bouts, which suggests that the birds were restless rather than resting.3. Interrupted rest was sometimes caused by birds standing on each other; on other occasion it may have served to increase heat loss.4. The frequency and duration of eating and drinking amongst individuals was variable. Neither dust‐bathing nor agonistic behaviour were observed and their absence may reflect the lack of importance of these behaviour patterns in meat chickens.
Article
Selection pressure for production traits in modern lines of poultry has placed increasing demands on skeletal integrity. Disruption of the normal process of skeletal growth and homeostasis results in bone diseases that are manifest throughout the modern poultry industry. Bone conditions in poultry can be grouped under three headings based on the age and type of fowls affected, and are indicative of the genetic and production stresses applied to the skeleton. In broilers during growth it is primarily pathologies of the growth plate that lead to most skeletal disorders. In broiler and turkey breeding stock the progressive degeneration of the articular cartilage results in osteoarthrosis, lameness and a consequential loss of reproductive performance. In laying hens bone fragility is most frequently the result of osteoporosis. Before attempting to determine the aetiology of a skeletal disorder an accurate diagnosis must be made. Only then can short- and long-term strategies be developed for the prevention and control of skeletal disorders. Diagnosis requires gross and histological examination, and also dietary, environmental and management analyses. The pathology often reflects lesions initiated when the bird was considerably younger and analyses must extend to assessing the factors prevalent during the initiation of lesions. Current studies are furthering the understanding of the aetiopathogenesis of avian skeletal disorders. For example, structural bone loss at the onset of follicular activity before egg-laying is pivotal to the development of osteoporosis in layers and deficiencies in growth factor expression are integral to the development of tibial dyschondroplasia.
Article
Research on ascites occurring in meat-type chickens reared at moderate and low altitude has shown that the pathogenesis is similar to that of the high altitude disease. Pulmonary hypertension (PH) caused by increased blood flow or increased resistance to flow in the lung results in right ventricular hypertrophy (RVH), valvular insufficiency, increased venous pressure and ascites. The structure of the avian heart, with its thin-walled right ventricle and muscular right atrioventricular valve, allows PH to induce heart failure quickly. The sudden increase in pulmonary hypertension syndrome (PHS) in meat-type chickens in the 1980s was associated with a rapid increase in growth rate and feed conversion. This was a result of a combination of genetic selection for fast-growing, heavy broilers with low feed conversion and a more dense, high caloric, pelleted food that supplied all the nutrients required for rapid growth and encouraged a high nutrient intake. PHS in meat-type chickens is usually primary pulmonary hypertension, that is, PH that occurs without evidence of prior heart or lung disease that could account for the increase in blood flow or resistance to flow that results in the increased pressure in the pulmonary arteries. The lungs of birds are firm and fixed in the thoracic cavity and they do not expand to draw air into the lung. The blood and air capillaries form a rigid network that allows only minimal expansion of the blood capillaries when more blood flow is required. Air is moved through the lung by abdominal movement which draws air in and out of the air sacs. The anatomy and physiology of the avian respiratory system are important in the susceptibility of meat-type chickens to PHS. The small stature of the modern meat-type chicken, the large, heavy breast mass, the pressure from abdominal contents on air sacs, and the small lung volume compared to body weight, may all be involved in the increased incidence of PHS. There is limited space for blood flow in the avian lung. Factors that increase blood flow or increase resistance to flow are additive. Increased blood viscosity caused by the polycythaemia of hypoxia, or increased erythrocyte rigidity of high Na (+), are more likely to produce PH in fast-growing than in slow-growing birds. Increased flow due to cold exposure is also additive. Ascites caused by PH is a production-related disease at low altitude. It can be prevented easily by restricting growth rate. It is possible that some meat-type chickens of the phenotype we have created have reached the limit of blood flow through their lungs and that future improvements in growth rate will only be possible if the lung and abdominal cavity capacities are enlarged.
Article
The extent to which degenerative hip disorders in adult male turkeys result in pain was investigated in a two-period crossover experiment. The birds in six pens received daily injections of an anti-inflammatory steroid (betamethasone) during week 1 and control injections of physiological saline in week 3. The turkeys in the other six pens received saline in week 1 and steroid in week 3. Behavioural observations of the birds during weeks 1 and 3 revealed that the steroid treatment resulted in more spontaneous activity. The steroid-treated birds also showed speedier movement in a sexual activity test in weeks 1 and 3. Post mortem examination revealed that all the turkeys were suffering from degenerative hip disorders. It is concluded that degenerative hip disorders in adult male turkeys result in a state of chronic pain which inhibits spontaneous activity and sexual activity.
Article
Marked changes have occurred in poultry production practices and in stocks bred for the production of meat and eggs. Of behavior pattern that originally favoured domestication, positive responses to humans and adaptability to environments are now most important. Development of specific strains for production of meat or eggs resulted in correlated responses in behavioural traits. Compared with egg strains, meat strains are docile and have excessive appetites, poor immunoresponsiveness and reduced motor ability. Genotype by environment interactions for behaviour limit inferences concerning responses of stocks across environments. Innate behaviour patterns and habituation processes can prevent some stimuli from causing physiological manifestations observed in general responses to stressors. Husbandry procedures should optimise phenotypic expressions of genetic potential to enhance well-being.
Article
1. Rapidly growing (meat-type) chickens have been intensively selected for over 50 years and grow up to four times faster than "layer" strains selected for reproductive traits. 2. Comparison between these lines are increasingly being used to study mechanisms underlying lean tissue growth. 3. Selection for increased growth has resulted in some undesirable consequences such as poor reproductive performance, excessive fatness, increased skeletal abnormalities and ascites. 4. The biochemistry, physiology and molecular biology of these changes are reviewed.
Article
A continuously increasing production level in poultry breeding has resulted in changes in metabolism. Selection procedures in breeding programmes are focused on an increase in growth rate and on a decrease in feed conversion ratio (less feed intake per unit of deposited tissue). These procedures do not pay attention to the maintenance requirements of birds. Imbalances between production (protein and fat deposition) and supply of energy for maintenance requirements lead to homeostatic dysregulation and to diseases of organs which supply the energy for production and maintenance. The alarming increase in metabolic diseases, such as heart failure syndrome, ascites, and oedema in the lungs and heart, can be directly related to an insufficient oxygen supply. A low oxygen consumption and heat production is one of the mechanisms by which a low feed conversion ratio can be achieved, as is induced hypothyroidism by which physical activity and thus heat production is reduced. Other diseases, such as liver cirrhosis, malabsorption syndrome, sudden death syndrome in broilers, and fatty liver-hemorrhage syndrome, which is nowadays the most important disease in laying hens in the Netherlands, can be related to an imbalance between the production rate and maintenance requirements. A continued selection on the basis of retained energy (in protein and fat) without paying attention to the maintenance requirements of birds will be detrimental for the health and welfare of poultry. These undesirable developments in poultry husbandry should be a challenge for sciences focused on welfare and stress in animals. Such a scientific approach to animals suffering from dysgenic changes in metabolism is needed to solve serious problems in poultry breeding.
Article
The relationships between the severity of lameness, the presence of tibial dyschondroplasia, and the frequency of dustbathing behaviour and duration of tonic immobility were studied in 96 broiler chicks kept from day-old in groups of four in wire-floored cages. Dustbathing was observed when the birds were given access for one hour to a tray containing sand or straw. The duration of tonic immobility and the severity of lameness were scored during weeks 3, 4, 5 and 6. After slaughter at 41 or 45 days of age the birds were examined for tibial dyschondroplasia; 34 birds were classified as having tibial dyschondroplasia and 54 had detectable lameness problems. Birds with tibial dyschondroplasia had a higher lameness score (P < 0.001), dustbathed on fewer days (P < 0.0001), and had longer periods of tonic immobility (P < 0.03) at six weeks than birds which did not have the condition. However, almost all the chicks, including those with tibial dyschondroplasia dustbathed on day 27 after they had not been given access to the tray for three days, significantly more than on days when they had not been deprived of the tray (P < 0.0001). Furthermore, lame birds and birds with tibial dyschondroplasia also dustbathed less with age. Studies of the vertical wing-shaking element of dustbathing confirmed that tibial dyschondroplasia reduced dustbathing (P < 0.05) and also showed that during the one-hour tests, sand resulted in more dustbathing than straw (P < 0.01).
Article
Lameness is prevalent among broiler chickens and there is concern that it is chronically painful. The administration of an analgesic has been frequently used to identify pain in lame farm animals. Therefore, in this study the ability of lame and normal broiler chickens to traverse an obstacle course was tested after treatment with the analgesic, carprofen, a placebo saline injection or a control handling procedure. Sound birds traversed the course in approximately 11 seconds, irrespective of treatment. Lame birds took approximately 34 seconds to traverse the course, unless they received carprofen, which reduced their completion time to 18 seconds. Thus, carprofen substantially increased the speed of lame birds, providing evidence that birds with moderate lameness suffer pain when they walk.
Article
Lame and sound broilers, selected from commercial flocks, were trained to discriminate between different coloured feeds, one of which contained carprofen. The two feeds were then offered simultaneously and the birds were allowed to select their own diet from the two feeds. In an initial study to assess the most appropriate concentration of drug, the plasma concentrations of carprofen were linearly related to the birds' dietary intake. The walking ability of lame birds was also significantly improved in a dose-dependent manner and lame birds tended to consume more analgesic than sound birds. In a second study, in which only one concentration of analgesic was used, lame birds selected significantly more drugged feed than sound birds, and that as the severity of the lameness increased, lame birds consumed a significantly higher proportion of the drugged feed.
Interactions between genotype and management factors in broilers
  • Sorensen
Sorensen, P., 1989. Interactions between genotype and management factors in broilers. In: Merat, P. Ed., Genotype and Environment Interactions in Poultry Production. Proc. 3rd European Symp. Poultry Welfare, Tours, France 50 World's Poultry Science Association, pp. 67-81. Ž.
Effect of lameness on feeding behaviour of broilers
  • Weeks
Weeks, C.A., Davies, H.C., 1996. Effect of leg weakness on feeding behaviour of broilers. Br. Poult. Sci. 37, 76-77, suppl.
Leg weakness in broiler chickens, a review of studies using gait scoring
  • S C Kestin
  • S J M Adams
  • N G Gregory
Kestin, S.C., Adams, S.J.M., Gregory, N.G., 1994. Leg weakness in broiler chickens, a review of studies using gait scoring. Proceedings of the 9th European Poultry Conference, Glasgow, UK Branch of WPSA II, 203-206.
Periodicity of behaviour of broilers at 4 and 6 weeks of age
  • A J F Webster
  • Oxford Blackwells
  • C A Weeks
  • H C Davies
Webster, A.J.F., 1994. Animal Welfare: A Cool Eye Towards Eden. Blackwells, Oxford. Weeks, C.A., Davies, H.C., 1995. Periodicity of behaviour of broilers at 4 and 6 weeks of age. Br. Poult. Sci. Ž. 36 5, 876-877.
Some activity patterns of meat chickens
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Preston, A.P., Pamment, P., McBride, G., Foenander, F., 1983. Some activity patterns of meat chickens. In: Fifth Australian Poultry and Stock Feed Convention, Adelaide. pp. 203-207.
Animal Welfare: A Cool Eye Towards Eden