Tina M Widowski

University of Guelph | UOGuelph · Department of Animal and Poultry Science, Campbell Centre for the Study of Animal Welfare

Diets fed to commercial chicken breeders are high in n-6 fatty acids (n-6 FAs) and low in n-3 fatty acids (n-3 FAs). N-3 FAs are essential for embryonic brain development. In precocial birds, like chickens, brain development and brain n-3 FA accrual occur primarily before hatching. In two experiments, broiler and layer breeders were fed diets with...

Feeding breeder hens diets enriched with omega-3 fatty acids (n-3 FA) has previously been shown to increase their progeny's immunocompetence. During an experiment to assess the effects of maternal-fed n-3 FA on broiler behaviour, broiler chickens experienced an unexpected disease outbreak. Here, we present the broiler offspring's body weight, unifo...

Individual variation in fearfulness can be modified during ontogeny, and high levels of fear can affect animal welfare. We asked whether early-life environmental complexity and genetic strain affect fear behaviour in young laying hens (pullets). Four replicates of brown (B) and white (W) genetic strains (breeds) of layers were each raised in four e...

Omega-3 fatty acids (n-3 FA) are fed to chickens to enrich eggs for human consumption. Feeding n-3 FA to breeder flocks could benefit the breeders and improve their offspring’s health, welfare, and productivity. This study assessed the impacts of feeding flaxseed (n-3 FA source) on broiler breeders’ and layer breeders’ production performance. In ex...

In flying birds, the pectoralis (PECT) and supracoracoideus (SUPRA) generate most of the power required for flight, while the wing feathers create the aerodynamic forces. However, in domestic laying hens, little is known about the architectural properties of these muscles and the forces the wings produce. As housing space increases for commercial l...

Producers are moving toward cage-free systems to house laying hens. These include aviary styles with multilevel wire enclosures and litter areas on the floor. In aviaries with doors hens can be confined within the tiered enclosure, which can be done to promote oviposition in nests and prevent hens from laying eggs in litter. However, there are mult...

Adult laying hens are increasingly housed in spatially complex systems, e.g., non-cage aviaries, where locomotion between elevated structures can be challenging for these gallinaceous birds. This study assessed the effect of early environmental complexity on spatial skills in two genetic strains. Brown (B) and white (W) feathered birds were raised...

Introduction To prepare laying hens for life in cage-free aviaries, they must be reared in aviaries that accustom them to the challenges of navigating a complex three-dimensional structure. Rearing aviaries vary in design and contain a brooding compartment in which chicks are confined during the first six weeks of age. These compartments vary great...

Adult laying hens are increasingly housed in spatially complex systems, e.g., non-cage aviaries, where locomotion between elevated structures can be challenging for these gallinaceous birds. This study assessed the effect of early environmental complexity on spatial skills in two genetic strains. Brown (B) and white (W) feathered birds were raised...

Unfit chicks with low viability are often euthanized in the layer industry. An effective euthanasia protocol is characterized by rapid, irreversible insensibility, followed by prompt death. This study was conducted to evaluate the efficacy of three cervical dislocation methods for killing layer chicks (2-3-day-old, avg BW ± SD; 44 ± 3 g, n = 40): m...

High fearfulness in commercial laying hens can negatively affect production parameters and animal welfare. Brown and white egg layers differ in several behavioral characteristics, though reported differences in fearfulness are inconsistent. A meta-analysis was conducted to determine whether there are systematic differences in measures of fearfulnes...

Domestic chickens may live in environments which restrict wing muscle usage. Notably, reduced wing activity and accompanying muscle weakness are hypothesized risk factors for keel bone fractures and deviations. We used radio-frequency identification (RFID) to measure duration spent at elevated resources (feeders, nest-boxes), ultrasonography to mea...

This chapter reviews key welfare concerns in poultry farming, including consequences of genetic selection for high productivity, intensive housing, and management procedures. Selection for fast growth in meat birds has resulted in conformational changes that affect mobility and breeder stocks that must be feed restricted to remain healthy. Calcium...

Feather loss in domestic chickens can occur due to wear and tear, disease or bird-to-bird pecking. Flight feather loss may decrease wing use, cause pectoral muscle loss and adversely impact the keel bone to which these muscles anchor. Feather loss and muscle weakness are hypothesized risk factors for keel bone fractures that are reported in up to 9...

The impact of varying light intensities on layer pullets is not yet well understood. Behaviorally, brighter illumination may increase pullet activity levels by allowing better navigation in the complexity of non-cage systems. In addition, light intensity was previously demonstrated to affect the levels of calcium and phosphate regulating hormones i...

Current commercial strains of broiler breeders display reproductive dysregulation when fed to satiety, but they can achieve optimal hatching egg production under feed restriction. However, chronic feed restriction in broiler breeders is a welfare concern due to physiological and behavioral signs of hunger, lack of satiety, and frustrated feeding mo...

Ground-dwelling species of birds, such as domestic chickens ( Gallus gallus domesticus ), experience difficulties sustaining flight due to high wing loading. This limited flight ability may be exacerbated by loss of flight feathers that is prevalent among egg-laying chickens. Despite this, chickens housed in aviary style systems need to use flight...

Maternal effects have been reported to alter offspring phenotype in laying hens. In this study, we investigated the effects of maternal environment and maternal age on egg traits and offspring development and behaviour. For this, we ran two experiments. First (E1), commercial hybrid hens were reared either in aviary or barren brooding cages, then h...

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...

This study was conducted to determine the differences in bone traits in 14 strains of broiler chickens differing in growth rate. The strains encompassed 2 conventional (CONV; ADG0-48>60 g/d) and 12 slower-growing (SG) strains classified as FAST (ADG0-62=53-55 g/d), MOD (ADG0-62=50-51 g/d), and SLOW (ADG0-62<50 g/d), with 4 strains represented in ea...

The effects of light intensity (L) are not well studied in pullets. Our research objective was to study the effect of L on navigational success, behavior, and welfare of two pullet strains (S). In two repeated trials, a 3 × 2 × 4 factorial arrangement tested three L (10, 30, 50 lux) and two S (Lohmann Brown-Lite (LB), LSL-Lite (LW)) at four ages. O...

In Canada, cattle must be unloaded, fed, watered, and rested after 36 h of transport; however, little is known about what constitutes appropriate rest station conditions. The objective of this study was to determine the relationship between providing straw bedding (14-cm deep) and trip, load, and commercial rest station characteristics, on lying be...

Maternal effects can shape the phenotypes of offspring, but the extent to which a layer breeder’s experience can affect commercial laying hens remains unclear. We aimed to investigate the effects of maternal age and maternal environment on laying hens’ behaviour and stress response. In our first experiment (E1), commercial hybrid hens were reared e...

The development of the musculoskeletal system is influenced by bird activity, which can be impacted by light intensity (L). The objective of this study was to determine the effect of L on the growth and bone health of Lohmann Brown-Lite (LB) and Lohmann LSL-Lite (LW) pullets. Three L treatments (10, 30 or 50 lux, provided by white LED lights) were...

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 t...

Rearing environment and genetic variation can affect behavioural and physical development. Successful navigation of cage-free laying hen housing (e.g. aviaries) requires both physical and cognitive navigation skills that develop early in life. Laying hens raised in rearing aviaries (RA) can have different experiences depending on the design of the...

Maternal effects have been reported to alter offspring phenotype in laying hens. In this study, we investigated the effects of maternal environment and maternal age on egg traits and offspring development and behaviour. For this, we ran two experiments. First (E1), commercial hybrid hens were reared either in aviary or barren brooding cages, then h...

Selection for accelerated growth rate and high breast yield in broiler chickens have been associated with an increase in myopathies, including wooden breast (WB) and white striping (WS). To investigate effects of growth rate on carcass traits and incidence of myopathies, 14 strains were evaluated, encompassing 2 conventional (CONV; strains B and C:...

Fear and aggression in dogs within veterinary clinics can lead to canine welfare impairments and pose a safety concern for veterinary staff. However, few studies have explored potential underlying causes for this fear and aggression. We used an online cross-sectional survey targeted to current dog owners to examine risk-factors associated with fear...

Growth performance, organ weight, ceca digesta short chain fatty acids (SCFA), jejunal histomorphometry, tibia ash, apparent retention (AR) of components and caloric efficiency were investigated in broiler chicken strains differing in growth rate fed diets with multi-enzyme supplement (MES). The strains differed in estimated time to reach 2.1 kg BW...

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 t...

• There is a need for humanely killing moribund or injured broiler birds on-farm with no reasonable chance of recovery. Two experiments evaluated the efficacy of three commercially applicable killing methods; manual cervical dislocation (CD), mechanical cervical dislocation with the Koechner Euthanizing Device (KED) and a non-penetrative captive bo...

Maternal effects can shape the phenotypes of offspring, but the extent to which a layer breeder’s experience can affect commercial laying hens remains unclear. We aimed to investigate the effects of maternal age and maternal environment on laying hens' behaviour and stress response. In our first experiment (E1), commercial hybrid hens were reared e...

Previous research indicates that the musculoskeletal development of pullets is improved when pullets are reared in aviaries compared to conventional rearing cages. However, there are considerable differences in rearing aviary design. To measure locomotion and musculoskeletal development of brown (n = 7) and white-feathered (n = 8) strains of pullet...

Selection for accelerated growth rate and high breast yield in broiler chickens have been associated with an increase in myopathies, including wooden breast (WB) and white striping (WS). To investigate effects of growth rate on carcass traits and incidence of myopathies, 14 strains were evaluated, encompassing 2 conventional (CONV; strains B and C:...

To meet the growing consumer demand for chicken meat, the poultry industry has selected broiler chickens for increasing efficiency and breast yield. While this high productivity means affordable and consistent product, it has come at a cost to broiler welfare. There has been increasing advocacy and consumer pressure on primary breeders, producers,...

Objective: To evaluate the influence of owner presence on behavioral and physiologic indicators of fear in dogs during routine physical examinations. Animals: 32 client-owned dogs. Procedures: Dogs underwent a standardized, video-recorded examination consisting of 6 phases (examination of the head, lymph node palpation, body palpation, axillar...

To meet the growing consumer demand for chicken meat, the poultry industry has selected broiler chickens for increasing efficiency and breast yield. While this high productivity means affordable and consistent product, it has come at a cost to broiler welfare. There has been increasing advocacy and consumer pressure on primary breeders, producers,...

Stressors experienced by layer breeders during egg production can lead to changes in the egg hormone content, potentially impacting their offspring, the commercial layers. Genetic differences might also affect the offspring's susceptibility to maternal experiences. In this study, we tested if maternal stress affects measures of stress and fear in f...

Consumers ascribing value to animal welfare related attributes has become a common interest for various stakeholders. This study investigated heterogeneous consumer preferences for eggs from the welfare enhanced production systems, and further, how the effects of information regarding these production systems depended on consumers’ previous purchas...

We investigated effects of rearing cage type and dietary limestone particle size (LPS) on egg production, egg weight, eggshell and bone quality in laying hens. The pullets were reared in conventional (CON; 20 chicks/cage, 270 cm²/chick) or furnished (FUR; 30 chicks/cage; 636 cm²/chick) cages and fed three LPS (fine, <0.595mm, F; medium, 0.595 to <1...

The objective of this study was to evaluate effects of environmental enrichment on play behaviour in fast-growing broiler chickens. Chicks (19 of each sex) were randomly assigned to 6 non-enriched (NE) pens and 6 pens enriched (E) with a raised platform, hanging weighing scale, peck stone, and suet feeder filled with wood shavings which was refille...

Body: Wooden breast (WB) and white striping (WS) are myopathies observed in conventional broiler chickens. Selection for slower growth has been suggested to reduce these disorders. This study compared carcass traits and the incidence of WB and WS among 2 conventional (CO) and 9 slow-growing (SL) broiler strains. Using a randomized incomplete block...

Laying hen housing is shifting from caged housing to alternative housing systems. While allowing for more species-specific behaviours, the complexity of aviary housing can be challenging for hens. Increased risk of injury and inability to access resources can negatively affect laying hen welfare. Commercial rearing aviaries are intended to prepare...

As housing laying hens in aviaries becomes more common, understanding relationships between social context and performance of key behaviors, such as dust bathing, is important. Expression of behaviors may be increased or repressed by the presence of conspecifics, and degree of behavioral synchrony can affect per hen resource allocation. We investig...

Effects of rearing cage type and dietary limestone particle size (LPS) on growth, apparent retention (AR) of nutrients and bone quality were investigated. The treatments were arranged in a 2 x 3 factorial with cage (conventional, CON; and furnished, FUR) and LPS (fine, <0.595mm, F; medium, 0.595 to <1.68mm, M; and 1:1 mixture of F and M wt/wt; FM)....

There are few published studies on the effect of stocking density (SD) of pullets, particularly between different genetic lines. The objectives of this study were to determine if strain or SD affects musculoskeletal development of pullets and determine any impact on the productivity and keel bone health of adult hens. Lohmann Selected Leghorn Lite...

This study investigated how the CO2 concentration within a chamber affects the efficacy of CO2 euthanasia, and how the efficacy of CO2 induction methods change as birds age. In experiment one, pairs of broiler chicks (n=192; 0, 3 and 6 days of age), were immersed into a chamber pre-filled with 70, 80, 90 or 100% CO2. For experiment two, 3 and 6 day...

Due to genetic selection for fast growth and high breast meat yield, commercial strains of broiler chickens and broiler breeders are predisposed to high feed intake; however, feeding broiler breeders ad libitum impairs their health and reproductive performance. Broiler breeders are feed-restricted throughout rearing to maintain health and performan...

Maternal stress can affect the offspring of birds, possibly due to hormone deposition in the egg. Additionally, phenotypic diversity resulting from domestication and selection for productivity has created a variety of poultry lines that may cope with stress differently. In this study, we investigated the effects of maternal stress on the behavior o...

Broiler breeders are feed-restricted during rearing to avoid the negative consequences of obesity during lay due to their genetic potential for fast growth rate. Feed restriction leads to chronic hunger, frustration and lack of satiety as indicated by hyperactivity, restlessness and oral-redirected behaviours that can become abnormal repetitive beh...

Emerging market differentiation for broiler meat from strains exhibiting a range of growth rates is necessitating comparative research on various physiological and production aspects of these strains. The objective of the present study was to compare select gastrointestinal, tibial, and plasma attributes in a sample of 48-day-old (50 male and 50 fe...

Background: Feather damage (FD) resulting from feather pecking remains a concern in non-cage housing systems for laying hens worldwide. This study aimed to identify bird-, housing-, and management-related factors associated with FD in non-cage housing systems as the egg production sector phases out the conventional cage system in Canada. A survey...