[show abstract][hide abstract] ABSTRACT: Chronic stress is a long-lasting negative emotional state that induces negative consequences on animals' psycho-physiological state. This study aimed at assessing whether unpredictable and repeated negative stimuli (URNS) influence feeding behaviour in quail. Sixty-four quail were exposed to URNS from day 17 to 40, while 64 quail were undisturbed. Two lines divergently selected on their inherent emotionality were used to assess the effect of genetic factors on the sensitivity to URNS. All quail were submitted to a sequential feeding procedure (using two diets of different energetic values) which placed them in a contrasting situation. Behavioural tests were performed to assess the emotional reactivity of the two lines. Results confirmed that differences exist between them and that their emotional reactivity was enhanced by URNS. Diet preferences, motivation and daily intake were also measured. URNS did not change the preferences for the hypercaloric diet compared to the hypocaloric diet in choice tests, but they reduced daily intakes in both lines. Motivations for each diet were differently affected by URNS: they decreased the motivation to eat the hypercaloric diet in quail selected for their low inherent fearfulness whereas they increased the motivation to eat the hypocaloric diet in quail selected for their high inherent fearfulness, which suggested a devaluation process in the former and a compensatory behaviour in the later. Growth was furthermore reduced and laying delayed by URNS in both lines. In conclusion, the exposure to URNS induced interesting changes in feeding behaviour added with an increase in emotional reactivity and an alteration of production parameters. This confirms that both lines of quail experienced a chronic stress state. However differences in feed motivation and emotional reactivity between lines under chronic stress suggested that they experienced different emotional state and use different ways to cope with it depending on their genetic background.
PLoS ONE 01/2014; 9(2):e87249. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Compared to rodents, the relationship between anxiety and cognitive performances has been less studied in birds. Yet, birds are frequently exposed to stimulations that constitute a potential source of anxiety and can affect their adaptation to their living conditions. The present study was aimed at evaluating, in birds, the relationship between levels of anxiety and object habituation and discrimination with the use of Japanese quail lines divergently selected for a fear response, tonic immobility. Previous studies demonstrated that the selection programme has modified the general anxiety trait of the birds. The task consisted in 4 daily sessions of 8 successive presentations of the same object in the home cage of the quail in order to habituate each bird to the object. The observation that both quail with a high and a low anxiety trait progressively spent more time close to the object indicated that habituation occurred. Dishabituation was assessed during a single session of 8 presentations of a novel object. Only quail with a high anxiety trait exhibited significant discrimination. They spent significantly less time close to the novel object than to the habituated object. It is hypothesised that a high anxiety trait is associated with a more accurate processing of environmental cues or events resulting in better discriminative performances.
Behavioural brain research 05/2013; · 3.22 Impact Factor
[show abstract][hide abstract] ABSTRACT: BACKGROUND: Environmental challenges might affect the maternal organism and indirectly affect the later ontogeny of the progeny. We investigated the cross-generation impact of a moderate heat challenge in chickens. We hypothesized that a warm temperature-within the thermotolerance range- would affect the hormonal environment provided to embryos by mothers, and in turn, affect the morphology and behavioral phenotype of offspring. METHODOLOGYPRINCIPAL FINDINGS: Laying hens were raised under a standard thermal condition at 21°C (controls) or 30°C (experimental) for 5 consecutive weeks. A significant increase was observed in the internal temperature of hens exposed to the warm treatment; however plasma corticosterone levels remained unaffected. The laying rate was not affected, but experimental hens laid lighter eggs than the controls during the treatment. As expected, the maternal thermal environment affected yolk hormone contents. Eggs laid by the experimental hens showed significantly higher concentrations of yolk progesterone, testosterone, and estradiol. All chicks were raised under standard thermal conditions. The quality of hatchlings, growth, feeding behavior and emotional reactivity of chicks were analyzed. Offspring of experimental hens (C30 chicks) were lighter but obtained better morphological quality scores at hatching than the controls (C21 chicks). C30 chicks expressed lesser distress calls when exposed to a novel food. Unlike C21 chicks, C30 chicks expressed no preference for energetic food. CONCLUSIONSIGNIFICANCE: Our findings suggest that moderate heat challenge triggers maternal effects and modulate the developmental trajectory of offspring in a way that may be adaptive. This suggests that the impact of heat challenges on captive or wild populations might have a cross-generation effect.
PLoS ONE 02/2013; PLoS ONE 8(2): e57670. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: The social behavior of animals, which is partially controlled by genetics, is one of the factors involved in their adaptation to large breeding groups. To understand better the relationships between different social behaviors, fear behaviors and production traits, we analyzed the phenotypic and genetic correlations of these traits in Japanese quail by a second generation crossing of two lines divergently selected for their social reinstatement behavior. Analyses of results for 900 individuals showed that the phenotypic correlations between behavioral traits were low with the exception of significant correlations between sexual behavior and aggressive pecks both at phenotypic (0.51) and genetic (0.90) levels. Significant positive genetic correlations were observed between emotional reactivity toward a novel object and sexual (0.89) or aggressive (0.63) behaviors. The other genetic correlations were observed mainly between behavioral and production traits. Thus, the level of emotional reactivity, estimated by the duration of tonic immobility, was positively correlated with weight at 17 and 65 days of age (0.76 and 0.79, respectively) and with delayed egg laying onset (0.74). In contrast, a higher level of social reinstatement behavior was associated with an earlier egg laying onset (-0.71). In addition, a strong sexual motivation was correlated with an earlier laying onset (-0.68) and a higher number of eggs laid (0.82). A low level of emotional reactivity toward a novel object and also a higher aggressive behavior were genetically correlated with a higher number of eggs laid (0.61 and 0.58, respectively). These results bring new insights into the complex determinism of social and emotional reactivity behaviors in birds and their relationships with production traits. Furthermore, they highlight the need to combine animal welfare and production traits in selection programs by taking into account traits of sociability and emotional reactivity.
PLoS ONE 01/2013; 8(12):e82157. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Emotionality trait influences exploratory behaviour in Japanese quail. Diazepam decreases impact of emotionality on exploratory behaviour. Selection on tonic immobility response represents valuable model of bird anxiety. a b s t r a c t This study tested whether lines of Japanese quails divergently selected for a fear response, the tonic immobility, might constitute a reliable bird model for studying anxiety. Previous studies demonstrated that the selection modifies the general underlying emotionality of the birds rather than exerting its effect only on tonic immobility. The behavioural effects of intraperitoneal injections of diazepam, an anxiolytic drug, were assessed in two lines of quail selected either for their short (STI) or long (LTI) duration of tonic immobility. Effects of diazepam were examined in two tests used for measuring emotionality in birds, the open field and the tonic immobility tests. After being placed in the centre of the open field, birds with a high emotionality (LTI quails) stayed longer in the centre of the apparatus than STI quail. Diazepam had anxiolytic effect in LTI birds as it increased the time spent in the outer area. This effect of diazepam appears to be selective because the drug has no effect on other behaviours such as distress calls or escape attempts. The drug has also no effect on the tonic immobility response in any of the two lines. These findings reveal an "anxiogenic" trait of LTI birds in the open field test that can be modulated by the administration of an anxiolytic drug. Therefore quails selected for LTI and STI represent a valuable model to study the mechanisms underlying anxiety in birds.
Behavioural brain research 01/2013; 237:124-128. · 3.22 Impact Factor
[show abstract][hide abstract] ABSTRACT: BACKGROUND: Slow-growing lines are widely used in France for the production of high quality free-range chickens. While such production is mainly dedicated to the whole carcass market, new prospects are opening up for the development of cuts and processed products. Whether the body composition and meat quality of slow-growing birds can be improved by selection has thus become an important issue. The genetic parameters of growth, body composition and breast meat quality traits were evaluated in relation to behaviour at slaughter in a large pedigree population including 1022 male and female slow-growing birds. RESULTS: The heritability coefficients (h2) of body weight and body composition traits varied from 0.3 to 0.5. Abdominal fat percentage was genetically positively correlated with body weight but negatively correlated with breast muscle yield. The characteristics of the breast meat (i.e., post-mortem fall in pH, colour, drip loss, shear-force and lipid content) were all heritable, with h2 estimates ranging from 0.18 to 0.48. The rate and extent of the fall in pH were under different genetic control. Strong negative genetic correlations were found between the ultimate pH and the lightness, yellowness and drip loss of the meat. Wing flapping on the shackle line was significantly heritable and exhibited marked genetic correlations with the pH at 15 min post-slaughter and the redness of the meat. The genetic relationships between meat quality traits, body weight and body composition appeared slightly different between males and females. CONCLUSION: This study suggested that there are a number of important criteria for selection on carcass and breast meat quality in slow-growing birds. Selection for reduced abdominal fatness and increased breast muscle yield should be effective as both traits were found to be highly heritable and favourably correlated. Substantial improvement in meat quality could be achieved by selection on ultimate pH which was highly heritable and strongly correlated with the colour and water-holding capacity of the meat. Moreover, this study revealed for the first time that the behaviour at slaughter is partly genetically determined in the chicken.
[show abstract][hide abstract] ABSTRACT: 1. Footpad dermatitis (FPD) is a recognised welfare problem in broiler chickens. Broiler feet (n = 54) were examined macroscopically and microscopically to determine a reliable correspondence between macroscopic and histological features, and to devise a scoring system that was relevant to bird welfare and easy to use at processing plants. 2. Three types of footpad lesion were defined based on their severity. Type I were mild lesions, visually characterised by scale enlargement and erythema, and histologically by hyperplasia and hyperkeratosis of the epidermis, superficial dermal congestion and oedema. Type II were moderate, superficial lesions, visually characterised by hypertrophic and hyperkeratotic scales covered with yellowish to brownish exudate, and histologically by a prominent pustular and crust-forming dermatitis. Type III lesions were the most pronounced, visually characterised by a thick dark adherent crust, and histologically by extensive ulceration. 3. On the basis of the severity and extent of these three types of lesions, a 5-point scale was devised, i.e. no or type I lesion (score 1), type II lesion (<50% or >50% of footpad, scores 2 and 3 respectively) and type III lesion (<50% or >50% of footpad, scores 4 and 5 respectively). 4. The scoring system has the advantage of making sense in terms of welfare compared with previous schemes. Furthermore, it is histologically validated and easy to use for the routine assessment of broiler welfare in processing plants.
British Poultry Science 06/2012; 53(3):275-81. · 1.15 Impact Factor
[show abstract][hide abstract] ABSTRACT: Chronic stress is known to enhance mammals' emotional reactivity and alters several of their cognitive functions, especially spatial learning. Few studies have investigated such effects in birds. We investigated the impact of a two-week stress on Japanese quail's emotional reactivity and spatial learning. Quail is an avian model widely used in laboratory studies and for extrapolation of data to other poultry species. As sensitivity to chronic stress can be modulated by intrinsic factors, we tested juvenile female Japanese quail from three lines, two of them divergently selected on tonic immobility duration, an indicator of general fearfulness. The different emotional reactivity levels of quail belonging to these lines can be revealed by a large variety of tests. Half of the birds were submitted to repeated unpredictable aversive events for two weeks, whereas the other half were left undisturbed. After this procedure, two tests (open field and emergence tests) evaluated the emotional reactivity of treated and control quails. They were then trained in a T-maze for seven days and their spatial learning was tested. The chronic stress protocol had an impact on resting, preening and foraging in the home cage. As predicted, the emotional reactivity of treated quails, especially those selected for long tonic immobility duration, was higher. Our spatial learning data showed that the treatment enhanced acquisition but not memorization. However, intrinsic fearfulness did not seem to interact with the treatment in this test. According to an inverted U-shaped relationship between stress and cognition, chronic stress can improve the adaptability of birds to a stressful environment. We discussed the mechanisms possibly implied in the increase of emotional reactivity and spatial abilities.
PLoS ONE 01/2012; 7(10):e47475. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Because of the increasing demand for raw cuts and processed products, there is a trend to producing very heavy broilers. Breeds that are used for such kinds of production have been intensively selected for growth rate and breast meat yield, and birds are reared for a longer period than standard broilers. This study was to evaluate the effects of increasing slaughter age on technical and economic factors, including production efficiency and environmental costs, bird welfare, and breast meat quality in a modern heavy broiler line. Five groups of 300 male Ross 708 chickens were reared until slaughter ages of 35, 42, 49, 56, or 63 d. Increasing age at slaughter from 35 to 63 d resulted in a 7.4-fold increase (P < 0.01) in mortality rate (5.21 vs. 0.70%). It also increased (P < 0.001) the slaughter weight and ADFI of birds 2.5- and 1.4-fold, respectively, without affecting their G:F. Under our experimental conditions, economic profit evaluated through the net gain reached a maximum at 42 d. The moisture and ammonium content of litter increased (P < 0.05 and P < 0.01, respectively) rapidly during rearing concomitantly with increased (P < 0.05) occurrence and severity of contact dermatitis and decreased (P < 0.05) walking ability and activity of birds. Thermal comfort also decreased (P < 0.05) greatly as early as 42 d of age. Changes in carcass quality occurred mainly between 35 and 56 d of age, with a progressive increase (P < 0.001) in breast and leg yield, whereas body fatness was barely affected by age. Major changes in breast meat traits were observed between 35 and 49 d of age, with an increase in muscle pH at 15 min (P < 0.01) and 24 h (P < 0.001) postmortem and reduced (P < 0.001) lightness and drip loss. The protein and lipid content of raw breast meat also increased (P < 0.05 and P < 0.01, respectively) with age. Taking into account the main aspects of sustainability, we could recommend slaughtering chickens of heavy line at 42 d of age.
Journal of Animal Science 12/2011; 90(6):2003-13. · 2.09 Impact Factor
[show abstract][hide abstract] ABSTRACT: Like mammals, bird embryos are capable of chemosensory learning, but the ontogeny of their feeding preferences has not been examined. We tested if the timing of stimulation in chicken embryos modulates the impact of in ovo olfactory stimulation on later food preferences. We exposed chicken embryos to an olfactory stimulus for a 4-day period in the middle or toward the end of the incubation period. The chicks were tested for their preference between foods with and without the olfactory stimulus in 3-min choice tests and on a 24-h time scale. Regardless of the type of food (familiar or novel) or the duration of the test, the control chicks not exposed to the olfactory stimulus consistently showed significant preferences for non-odorized foods. Chicks that were exposed in ovo to the olfactory stimulus did not show a preference for odorized or non-odorized foods. Only those chicks that were exposed to the olfactory stimulus toward the end of the incubation period differed from the controls and incorporated a higher proportion of odorized food into their diets on a 24-h time scale. This result indicates that olfactory stimulation at the end of embryonic development has a stronger impact on later feeding preferences. Our findings contribute to the growing pool of recent data appreciating the impact of olfactory signals on behavior regulation in avian species.
Chemical Senses 11/2011; 37(3):253-61. · 3.22 Impact Factor
[show abstract][hide abstract] ABSTRACT: There is considerable variability in the susceptibility of individuals to the adverse effects of chronic stress. In humans and other mammals, individual traits such as high anxiety are proposed as a vulnerability factor for the development of stress-related disorders. In the present study, we tested whether a similar behavioural trait in birds, higher emotional reactivity, also favours the occurrence of chronic stress-related behavioural and physiological dysfunction. For this, lines of Japanese quail divergently selected for a typical fear response in birds, the duration of tonic immobility, were subjected to unpredictable aversive stimulation over 2 weeks. Previous studies demonstrate that the selection program modifies the general underlying emotionality of the birds rather than exerting its effect only on tonic immobility. Interestingly, only birds selected for their higher emotionality exhibited significantly enhanced latency to first step and decreased locomotor activity in the open-field test after exposure to chronic stress compared to non-stressed control birds. This effect of chronic stress was selective for the tested dimension of bird emotional reactivity because there was no observed effect on the tonic immobility response. Moreover, chronically stressed birds selected for their higher emotionality exhibited significantly decreased basal corticosterone levels, a physiological marker of stress. These findings show that chronic stress is associated with changes in emotional reactivity and related physiological markers in birds. They also highlight emotional reactivity as an important predisposing factor for the occurrence of the adverse effects of chronic stress in birds.
Behavioural brain research 08/2011; 225(2):505-10. · 3.22 Impact Factor
[show abstract][hide abstract] ABSTRACT: En élevage, les animaux sont soumis à des stimulations négatives (SN), répétées et
imprévisibles qui peuvent avoir des conséquences sur leur comportement et leur bien-être.
Pour tester cette hypothèse, deux groupes de cailles (12 mâles et 12 femelles chacun) ont été
constitués : un groupe a été exposé quotidiennement à des SN imprévisibles (e.g. bruits
soudains, contentions, environnement nouveau, agitation de la cage…) de l'âge de 17 à 61
jours, tandis que le groupe témoin n'était pas exposé. Des tests comportementaux (réactivité à
l’homme, j31 ; immobilité tonique, j42-j63 ; objet nouveau, j64 ; contention, j64), des budgets
temps (j30-j51) et des mesures de corticostérone (j65-j66) ont été réalisés sur les deux
Les animaux stimulés se toilettent plus à j30 et j51, et sont plus actifs à j30 que les témoins.
Ils ont également tendance à être plus éloignés de l’homme, placé devant la cage, que les
témoins. De plus, les cailles stimulées restent davantage immobiles lors de la contention.
Chez les mâles stimulés, i/ le nombre d’inductions nécessaire pour induire le comportement
d’immobilité tonique est plus élevé que chez les témoins à j42 mais cet effet disparaît à j63, et
ii/ l'objet nouveau est picoré moins et plus tard que les témoins à j64. Avec ou sans SN, les
mâles sont plus actifs que les femelles, présentent un taux de corticostérone plus élevé et
nécessitent un plus grand nombre d'inductions avant d'être en immobilité tonique.
Les SN utilisées modifient l’activité spontanée et augmentent la réactivité émotionnelle des
cailles, quel que soit leur sexe, même si les mâles peuvent apparaître plus réactifs dans
certaines situations. Les résultats suggèrent que mâles et femelles expriment différemment
leur état de stress ce qui s'explique probablement par des différences plus générales de
comportement et de physiologie entre les sexes.
Colloque de la Société Française pour l'Etude du Comportement Animal; 05/2011
[show abstract][hide abstract] ABSTRACT: Social bonds between groupmates and social motivation can influence the stability of the social structure among domestic birds. Group size may also influence social stability, but no information is available about its influence on social bonding. We investigated the effect of group size and social motivation on the strength of social bonds between familiar Japanese quail chicks. The behaviour of quail selected for high (HSR) or low (LSR) social reinstatement behaviour and housed in different group sizes (6, 15 and 30 individuals) was recorded during two successive 10 min situations: separation and return of a cagemate or an unfamiliar conspecific. In both lines and for all group sizes, chicks formed social bonds with cagemates, shown by disturbance at separation and a greater calming effect of the return of a familiar versus an unfamiliar quail. LSR chicks might form stronger social bonds than HSR ones but our results do not allow us to conclude confidently on that point. With increasing group size, the calming effect and especially the positive social interactions decreased in both lines, indicating a weakening of the social bond between familiar conspecifics, perhaps because of the larger number of potential partners or the establishment of a tolerant social strategy based on less aggression, less time spent in contact and weaker bonds. Further investigations of the relationship between group size and social bonding in this species may allow us to determine why their social behaviour changes with increasing group size and to make more suitable social environments for domestic birds.
[show abstract][hide abstract] ABSTRACT: Chronic stress is known to induce long term alterations of emotional behaviours as well as cognitive performances leading thereby to welfare or husbandry problems. These stress-induced consequences are observed following long periods of stress lasting from several weeks to several years. The current study examined whether a shorter period of stress (one week) produced similar impairing effects. Two-week old Japanese quail were either submitted to a series of aversive events over consecutive 8 days, at unpredictable times each day (treated animals) or left undisturbed (controls). Following the treatment period, animals were weighed and basal as well as aversive events-induced levels of plasma corticosterone were quantified. Quail were also tested for emotional reactivity in three tests (the tonic immobility test, the hole-in-the-wall and novel object tests) and for spatial reference memory. Although there was no difference in corticosterone levels between the two groups, the treated animals had lower body weight than controls. Behavioural investigations after the treatment period did not reveal any difference between the groups in the three emotional reactivity tests. In the spatial task, treated quail displayed enhanced behavioural flexibility as revealed by their higher performances during the reversal phase of the task. The alteration of growth suggests that a short period of repetitive exposures to unpredictable aversive events can be perceived by quail as stressful. Such a stress period can improve spatial learning performances in quail supporting the critical role played by the duration of the stress period on cognitive performance.
Behavioural brain research 10/2010; 217(1):104-10. · 3.22 Impact Factor
[show abstract][hide abstract] ABSTRACT: In several mammalian species, prenatal exposure to odours can elicit later positive consummatory behaviour in response to substrates bearing that odorant. In birds, the sense of smell has been considerably underestimated, and very little is known about the effects of early sensory experience on the regulation of feeding behaviour. We tested the hypothesis that the feeding behaviour of the domestic chicken could be regulated by olfactory learning during the embryonic life. To that end, chicken embryos were exposed to an olfactory stimulus (blend of essential oil of orange and nature identical vanillin) from embryonic day (ED) 12 to ED20, and chicks were tested between 4 and 9 d of age. In short-term choice tests, at day 4 and 5, chickens previously exposed to a low concentration (LC) of the olfactory stimulus spent a higher proportion of time eating a familiar or an unfamiliar food bearing the olfactory stimulus compared to non-exposed control chickens. Conversely, chickens previously exposed to a high concentration (HC) of the olfactory stimulus were found to avoid all foods bearing the olfactory stimulus. On a 24- h time scale at day 7–8, LC and HC birds, but not controls, ingest significantly less familiar food containing the olfactory stimulus. This result indicated a long-term effect of the early olfactory experience on feeding preferences. We demonstrated that chickens can utilize information from their pre-hatch chemosensory environment to guide their later feeding behaviour. A pre-hatch effect of the intensity of odour signals in the regulation of feeding behaviour is reported here for the first time.
[show abstract][hide abstract] ABSTRACT: Repeated encounters with unfamiliar conspecifics in large groups of domestic birds create a potentially stressful social environment which can affect the birds’ emotional reactivity and consequently their welfare. As social relationships between young quail are particularly influenced by their social motivation (i.e., the motivation to seek close proximity with conspecifics), it is likely that the reaction of quail to repeated encounters with strangers depends on their social motivation. The aim of this study was to assess the emotional reactivity of quail chicks with high (HSR) or low (LSR) social motivation housed under stable and unstable social conditions. Quail chicks were housed either in stable pairs, i.e. remaining with the same cagemate until testing (NHSR=19 and NLSR=18 pairs), or in unstable pairs, i.e. changing cagemate daily from 6 to 13 days of age (NHSR=20 and NLSR=19 pairs). Emotional reactivity was measured using a novel object test on day 14, and an emergence test and a tonic immobility test on day 15. The social condition affected the number of induction attempts of quail chicks in the tonic immobility test but only in the LSR ones. This number of inductions was lower under the stable than under the unstable social condition in this line. Moreover, the HSR chicks showed greater disturbance than the LSR ones in the three behavioural tests. In conclusion, social instability did not affect the emotional reactivity of HSR quail chicks, which was high, regardless of social condition. In contrast, repeated cagemate changes seemed to decrease the emotional reactivity of LSR quail chicks. These results suggest that low social motivation makes easier the adaptation to the potential social instability encountered in large flocks.
[show abstract][hide abstract] ABSTRACT: Social bonds between conspecifics (sexual pairmates, parent–infant or siblings) and social motivation can influence the way birds interact. Social bonds between familiar conspecifics may also be formed, especially in chicks from precocial species in which behaviour is characterized by a strong social attraction. We investigated the establishment of such a bond and the effect of social motivation using a separation/reunion test in 1-week-old Japanese quail. In experiment 1, the behaviour of paired quail selected for high (HSR) or low (LSR) social reinstatement behaviour was recorded during three successive 10 min situations: baseline, separation and return of the cagemate. Both lines showed behavioural changes during social separation but the distress response was higher in the HSR line. Return of the familiar cagemate induced a return to baseline activity in both lines. The specificity of this response was tested in experiment 2 in which paired quail of both lines were separated, and their behavioural and vocal responses to the introduction of the familiar or an unfamiliar bird were compared. LSR chicks responded differently both behaviourally and vocally according to the familiarity of the introduced bird, whereas the response of HSR chicks differed only for aggressive pecks. HSR quail chicks thus revealed a nonspecific social attraction for conspecifics, whereas LSR chicks showed a bond with the cagemate. Our results highlight the importance of vocal communication as an indicator of the strength of the bond. Our findings show that high social motivation in quail chicks is not related to the development of a social bond.