Social discrimination in Japanese quail Coturnix japonica chicks genetically selected for low or high social reinstatement motivation

Attraction for familiar conspecifics in young chicks (Gallus gallus): An interbreed study

From the beginning of life, discriminating between familiar and unfamiliar individuals and staying in contact with conspecifics are important to establish social relationships. To better understand these early social behaviours, we studied the different responses to familiar/unfamiliar individuals in 4-day-old domestic chicks (Gallus gallus) in three genetically isolated breeds: Padovana, Polverara and Robusta maculata. Chicks discriminated between familiar and unfamiliar individuals, staying closer to familiar individuals. Social reinstatement and fear responses were measured as the average distance between subjects, the latency of the first step and exploration of the arena differed between breeds. More socially motivated chicks, that stayed in closer proximity, were less afraid of starting to move and explored the environment more extensively. Interbreed differences in social reinstatement indicate that social attraction shows genetic variability from the early stages of life.

Effect of chronic intracerebroventricular administration of an aromatase inhibitor on the expression of socio-sexual behaviors in male Japanese quail

Aromatase converts androgens into estrogens in the brain of vertebrates including humans. This enzyme is also expressed in other tissues where its action may result in negative effects on human health (e.g., promotion of tumor growth). To prevent these effects, aromatase inhibitors were developed and are currently used to block human estrogen-dependent tumors. In vertebrates including quail, aromatase is expressed in a highly conserved set of interconnected brain nuclei known as the social behavior network. This network is directly implicated in the expression of a large range of social behaviors. The primary goal of this study was to characterize in Japanese quail the potential impact of brain aromatase on sexual behavior, aggressiveness and social motivation (i.e., tendency to approach and stay close to conspecifics). An additional goal was to test the feasibility and effectiveness of long-term delivery of an aromatase inhibitor directly into the third ventricle via Alzet™ osmotic minipumps using male sexual behavior as the aromatase dependent measure. We demonstrate that this mode of administration results in the strongest inhibition of both copulatory behavior and sexual motivation ever observed in this species, while other social behaviors were variably affected. Sexual motivation and the tendency to approach a group of conspecifics including females clearly seem to depend on brain aromatase, but the effects of central estrogen production on aggressive behavior and on the motivation to approach males remain less clear.

Adrenocortical responses in Japanese quail classified by their permanence in proximity to either low or high density of conspecifics

The density-related permanence test (DRP) is used to classify young birds (while in groups) according to their individual permanence in proximity to either a high or low density of conspecifics (HD or LD, respectively). The birds' performance in DRP was associated with underlying differences in the social responses of their individuals. Quails in homogeneous groups of LD residents responded with less compact groups and higher levels of agonistic interactions to the presence of an intruder, and showed higher levels of agonistic interactions among cagemates than the homogeneous groups of HD birds. This study deepen the characterization of DRP evaluating whether contrasting behavior during test is associated with birds' stress responses to challenging situations during rearing. Plasma corticosterone responses were individually assessed after submitting DRP categorized birds to a brief (10 min) partial restraint (mechanical stressor; experiment 1), or after introducing them during 5 min as intruders in homogeneous groups of 6 unknown same category (HD or LD) conspecifics (social stressor; experiment 2). Experiment 1 showed that basal corticosterone levels were similar in all groups and the partial mechanical restraint induced an increase in plasma corticosterone concentration also in all groups. However, the increase induced by the stressor was higher in the LD birds than in their HD counterparts. In experiment 2, compared to controls, social stressor showed no plasma corticosterone changes in the intruders that were introduced in an unfamiliar group of HD conspecifics. However, intruders (both HD and LD) that were visiting the LD residents showed an increased corticosterone response compared to their control counterparts. Results suggest that categorization of birds in the DRP test could have relevance for selection programs oriented to obtain birds better suited to intensive rearing conditions that includes high density of animals and exposure to unavoidable stressors.

Place preferences of Japanese quail given a permanent choice between a social or a non-social but enriched situation

Japanese quail from two lines selected for high (HSR) or low (LSR) levels of social reinstatement behaviour were permanently placed from 2 days to 6 weeks of age in a situation where one tested animal had the choice between being in social contact with a stimulus animal in a bare compartment of the cage or out of visual contact with the stimulus animal in a relatively rich environment containing food, water and wood shavings. The young (1 or 2 weeks of age) quails spent most of their time (over 80%) in the social compartment, about 10% feeding and drinking, and about 10% performing other activities in the non-social compartment. Hardly any differences appeared between the two lines when 1 or 2 weeks old, but at 4 weeks of age the LSR quails started to decrease the time spent in the social compartment and this phenomenon only appeared at 6 weeks of age and to a lesser extent in the HSR quails. At 4 and 6 weeks the differences between lines were significant. The lack of difference between the two lines in young quails can be explained by the very high social motivation expressed even by LSR quails in the conditions of the study. When they are older line differences are expressed. This change coincides with the time when the natural coveys start to disperse and also with the beginning of sexual development. These results confirm the hypothesis of François et al. (François, N., Mills, A.D., Faure, J.M., 1997. Inter-individual distances in Japanese quail (Coturnix japonica) selected for high or low levels of sociability. Behav. Process. (in press)) that line differences in social motivation persist into adult or near adult life and can still be demonstrated, provided the circumstances are such that aggression does not prevent close social contact.

Effect of group disruption on social behaviour in lines of Japanese quail (Coturnixjaponica) selected for high or low levels of social reinstatement behaviour

Japanese quail of lines selected for high (HSR) or low (LSR) levels of social reinstatement (SR) behaviour were reared in groups of three. At 3 and 6 weeks of age, one group member was replaced with an unfamiliar conspecific bird. Behaviour following introduction of the intruder was similar at both ages. Quail of both lines spent more time immobile after introduction of the intruder than before its introduction. In the LSR, but not the HSR line, inter-individual distances between intruders and other chicks, were greater than those between familiar chicks. Birds of both lines pecked more between unfamiliar than between familiar birds. Pecks, not associated with escape or avoidance by the pecked bird, were more frequent in HSR groups. Selection for HSR behaviour appears to have increased non-aggressive exploration of intruder whereas selection for LSR behaviour has decreased interest in or increased shunning of intruders.

Social motivation affects the display of individual discrimination in young and adult Japanese quail (Coturnix japonica)

A simultaneous two-choice test was used to investigate discrimination between a familiar (F) and an unfamiliar conspecific (U) in Japanese quail, selected for high (HSR) or low (LSR) social reinstatement behavior (tendency to rejoin and stay close to conspecifics). Animals were 1-week unsexed and 6-week-old male quail. One-week-old LSR quail and 6-week-old male HSR quail displayed discrimination after 24 hr of pair contact (p < 0.05), and a tendency to discriminate (p < 0.10) was found in adult male LSR quail. After 1 week of pair contact, results were similar in LSR quail chicks, but no discrimination was evidenced in adult quail of either line. Therefore, Japanese quail are able to discriminate between a familiar cagemate and an unfamiliar conspecific after only 24 hr of pair contact. Moreover, this study reveals for the first time in this species that social motivation and age both influence the display of individual discrimination.

Investigating social discrimination of group members by laying hens

Social relationships in domestic fowl are commonly assumed to rely on social recognition and its pre-requisite, discrimination of group-mates. If this is true, then the unnatural physical and social environments in which commercial laying hens are typically housed, when compared with those in which their progenitor species evolved, may compromise social function with consequent implications for welfare. Our aims were to determine whether adult hens can discriminate between unique pairs of familiar conspecifics, and to establish the most appropriate method for assessing this social discrimination. We investigated group-mate discrimination using two learning tasks in which there was bi-directional exchange of visual, auditory and olfactory information. Learning occurred in a Y-maze task (p<0.003; n=7/8) but not in an operant key-pecking task (p=0.001; n=1/10). A further experiment with the operant-trained hens examined whether failure was specific to the group-mate social discrimination or to the response task. Learning also failed to occur in this familiar/unfamiliar social discrimination task (p=0.001; n=1/10). Our findings demonstrate unequivocally that adult laying hens kept in small groups, under environmental conditions more consistent with those in which sensory capacities evolved, can discriminate group members: however, appropriate methods to demonstrate discrimination are crucial.

Responses of Young Red Jungle Fowl (Gallus gallus) and White Leghorn Layers to Familiar and Unfamiliar Social Stimuli

Social preferences of familiar over unfamiliar social stimuli in chicks may be used to measure sociality, a characteristic important for the welfare of poultry in commercial production. We studied social preferences and reaction to strangers in young White Leghorns and red jungle fowl (Gallus gallus) in 3 tests. All chicks were raised and housed in 2 groups of 34 individuals per breed. At 24 to 29 d of age 38 chicks per breed were tested in 2 runway tests. In the first, chicks had a free choice between familiar and unfamiliar breed members, and in the second the choice was between unfamiliar chicks of their own breed and the other breed. On d 41 to 42, spacing and agonistic interactions of 28 pairs of chicks per breed (in half of the pairs, chicks were unfamiliar to each other) were observed in an open field for 10 min (pair test). In the first runway test, clear preference for familiar chicks and avoidance of unfamiliar social stimuli was found only in Leghorns, whereas both breeds showed a preference for their own breed members in the second runway test. Affiliation to the familiar breed, however, was more pronounced in Leghorns. In the pair test, Leghorns were significantly more involved in agonistic interactions than wild-type chicks. Avoidance of unfamiliar and preference for familiar conspecifics might suggest a weaker capacity of Leghorns to cope with novel social and environmental stimuli, which might have implications for the welfare of the birds in production environments when encountering unfamiliar individuals.

Effects of an acute stressor on fear and on the social reinstatement responses of domestic chicks to cagemates and strangers

Genetic selection for appropriate levels of sociality (motivation to be with conspecifics) could benefit poultry welfare and performance. Runway tests that require chicks to traverse a corridor in order to reach other chicks in a goal box are commonly used to measure this behavioural trait. However, we need to determine if the chicks' responses in such tests are sensitive to certain experiential variables before we can recommend possible selection criteria for future breeding programmes. The present study focused on fear and on the identity of the stimulus birds. Broiler chicks either remained undisturbed or were exposed to an acute stressor (mechanical restraint) before their tonic immobility fear responses were measured 1h later in Experiment 1. Exposure to the stressor significantly prolonged tonic immobility and, hence, presumably, underlying fear levels. In Experiment 2, the responses of stressed chicks and undisturbed controls were assessed when they were tested individually in a runway with a goal box containing either familiar or unfamiliar chicks of the same age. Our finding that stressed chicks emerged from the start box sooner and spent longer near the stimulus birds suggests that exposure to a frightening event increased social reinstatement motivation. Furthermore, social affiliation was more pronounced when the goal box contained familiar cagemates rather than strange chicks, regardless of prior treatment. This finding demonstrates that broiler chicks that were housed in groups of twelve can discriminate between familiar and unfamiliar conspecifics encountered in novel surroundings. Thus, sociality was positively associated with fearfulness and broilers clearly showed social discrimination in runway tests. These findings highlight the dangers of disregarding variables, such as fear and the capacity for social recognition in tests of social motivation. We strongly recommend that exposure to frightening events prior to test should be avoided and that the identity of the birds in the runway goal box should be standardized, i.e. either familiar or unfamiliar, and noted.

Domestic chicks' runway responses to video images of conspecifics

Because chickens are highly social animals, live conspecifics are often used to provide an incentive or goal in studies of gait, sociality or fear that require the bird to traverse a runway. However, the variable behaviour of the stimulus birds can influence the approach/avoidance responses of the test birds and thereby confound the results. Because chickens modify their behaviour readily and appropriately to a variety of video images, including social stimuli, we asked if video playback might represent easily controllable and standardized alternatives to live birds. Female ISA Brown chicks were housed in groups of eight and then exposed to a blank illuminated television for 10min per day from 2 to 7 days of age. At 8 or 9 days of age they were placed individually in the start box of a 1.6m long runway and we recorded their responses to a monitor displaying selected video images that was situated in the goal box at the opposite end of the runway. In Experiment 1 chicks approached a monitor playing the video image and soundtrack of feeding chicks significantly sooner than one of a goal box with the food dish and background noise. In Experiment 2, chicks were exposed to the same video of feeding conspecifics with or without the associated sounds or to a video of the goal box with or without the chick soundtrack. Both the videos of other chicks elicited faster approach than did those of the goal box and the sound and silent versions were equally attractive. Adding the soundtrack of feeding chicks to the goal-box video failed to increase its attractiveness. The present results suggest that chicks are attracted towards televised images of other chicks. They also indicate that the visual and auditory components of the video stimuli did not exert additive effects and that approach reflected attraction to the visual image. Collectively, our findings suggest that video playback of selected social stimuli, such as feeding conspecifics, could be a valuable tool in tests requiring voluntary locomotion along a predetermined path.

Ease of capture in lines of Japanese quail (Coturnix japonica) subjected to contrasting selection for fear or sociability

Japanese quail (Coturnix japonica) of lines, which have been subjected to contrasting selection for duration of the tonic immobility (TI) reaction or social reinstatement (SR) behaviour over many generations show corresponding differences in underlying fearfulness and sociality. As fearfulness and sociality are particularly influential traits in domesticated species, the finding that such traits respond to artificial selection may have important implications for poultry welfare and performance. However, it is not known if or how such selection has influenced human-animal interactions. The present experiment investigated the influence of fearfulness and SR behaviour on the ease with which birds could be caught and handled. Birds of lines selected for duration of the TI response or SR behaviour were reared in mixed line groups (LTI and STI or HSR and LSR) of 491 and 346 birds, respectively, until 6 weeks of age. When the birds were 2, 4, and 6 weeks of age, they were caught one by one and their individual capture ranks noted. In the group of birds selected for duration of the TI response, birds selected of the line selected for short duration of TI were caught before those selected for long duration of the response. In the group of birds selected for SR motivation, birds of the high line were caught before their low lines counterparts. Coefficients of concordance between capture ranks were significant and capture ranks did not differ significantly across ages. These results imply that selection for low levels of fear or high levels of sociality produces animals that are less disturbed by human interventions than animals selected for the opposite traits. The greater ease of capture of low fear line birds than high fear line birds may be explained by reduced fear of humans. The fact that the birds selected for high levels of SR behaviour are easier to catch than birds selected for low levels of sociality is less readily explicable. One hypothesis is that HSR line chicks tend to be more strongly imprinted on each other and the human caretaker. However, SR behaviour is highly species specific in both lines, existing evidence for line differences in social discrimination is limited and birds of the two lines show similar duration of the TI response. Despite this, whatever their underlying causation, these results demonstrate that genetic selection can be used to reduce negative reactions to human beings and may be of value in the improvement of both animal welfare and productivity.

Genetic Selection for Poultry Behaviour: Big Bad Wolf or Friend in Need?

Although genetic selection for certain characteristics has compromised the well-being of domestic animals, selective breeding could and probably should be used to improve welfare. Three of the major behavioural problems facing the poultry industry are fear, feather pecking and social stress. However, these and many other behavioural traits respond readily to genetic selection. The present paper reports the results of selective breeding studies in which underlying fearfulness, sociality, feather pecking, adrenocortical responsiveness, and growth rate were manipulated in Japanese quail, Coturnix japonica, or in chickens, Gallus gallus domesticus. The apparent benefits of selection for appropriate levels of these characteristics are discussed, as are the ethical issues involved. The ultimate aims of the selection programmes and the studies described here are to improve the birds ‘ welfare and productivity by increasing their ability to interact successfully with their physical environment, with one another, and with human beings.

Early T-maze behaviour and subsequent growth in commercial broiler flocks

Two batches of 2000 mixed-sex broiler chicks were obtained, one in summer and one in winter. Each flock was housed on the floor at a commercial farm. At 2 or 3 d of age, the latencies to escape from a T-maze were measured in 1044 and 1180 chicks in the summer and winter flocks, respectively. Chicks were assigned to high (HP), moderate (MP) or low (LP) performance categories if their escape latencies were below 40 s, between 40 to 90 s, or above 90 s, respectively. Ninety male and 90 female chicks from each of the 3 categories were weighed when they were 3 d old. The birds then remained undisturbed, apart from routine maintenance, until similar numbers were weighed at 49 d of age. Some birds may have been weighed at both ages. Body weights were higher in males than females and higher in the winter than summer flock at 3 d of age. Significant main effects of chick category as well as gender and season were found at 49 d of age. There were no significant interactions. As expected, 49-d body weights were higher in males than females and in the flock reared in winter than in summer. 5. HP chicks (those that showed rapid escape from the T-maze at 3 d) were also significantly heavier at 49 d than their LP counterparts, with MP chicks occupying an intermediate position. This suggests that early performance in a T-maze test is positively associated with subsequent growth. Furthermore, this relationship was apparent in each of the 2 flocks. Given this positive association, we suggest that this simple, rapid and non-invasive behavioural test could be a useful selection criterion for future breeding programmes.

T-maze behaviour in domestic chicks: a search for underlying variables

We investigated whether contrasting T-maze behaviour shown by domestic chicks, Gallus gallus domesticus, of a broiler strain reflected underlying differences in their general activity levels, fearfulness or sociality. The time taken by 2-day-old chicks to traverse a T maze and thereby regain visual contact with their companions was measured. Chicks were categorized according to whether they completed this task quickly (HP, high performance, <25 s) or slowly (LP, low performance, >75 s) and then housed in same-category groups, each of eight chicks. In experiment 1, we compared the numbers of HP and LP chicks showing certain home cage behaviours (ambulation, standing, resting, maintenance, pecking, preening). No significant differences were found. In experiment 2, we compared the behaviour of HP and LP chicks in two tests of sociality (home cage proximity, runway) and in two tests of fear (emergence, tonic immobility). The HP chicks stayed closer together in the home cage than did their LP counterparts and they spent significantly longer near a goal box containing conspecifics in the runway than did LP ones. Conversely, there were no significant differences between HP and LP chicks in their latency to emerge from a sheltered area into an exposed and, hence, potentially frightening one or in their tonic immobility fear reactions. These findings suggest that contrasting T-maze performance was unlikely to have reflected differences in underlying activity levels or in fearfulness. Conversely, individual variation in underlying sociality was probably an influential variable. Copyright 1999 The Association for the Study of Animal Behaviour.

Anxiogenic-like effects of Tagetes minuta L essential oil on T-maze and tonic immobility behaviour in domestic chicks

In a first experiment, four doses (ranging between 0.04 and 0.45 mg/kg of body weight) of the essential oil from Tagetes minuta L. were subcutaneously injected in two-day-old chicks and a dose-response curve assessed for escape performance in a T-maze test. The 0.1, 0.25 and 0.45 mg/kg doses impaired the first escape performance suggesting an anxiogenic-like effect of the essential oil. After 3 h the same chicks were tested for a second escape performance, without being injected again, and no differences were observed compared to controls, suggesting that the essential oil did not affect retention. Furthermore, the effects of the essential oil were observed in the three sections of the T-maze apparatus. So, the performance was impaired in the isolation chamber section, suggesting the induction of increased anxiogenic behaviour, and also in the mirror section, suggesting that the social reinstatement behaviour was modified by an increased anxiety level. Changes in the principal corridor section were not observed, suggesting that the locomotor activity was not affected by these oil doses. The second escape performance was not affected in any of the T-maze sections, confirming that these doses did not affect learning ability. In a second experiment, a middle dose of the essential oil (0.25 mg/kg) increased the tonic immobility reaction in 15 days old chicks similarly to an anxiogenic dose of FG 7142 (1 mg/kg), while an anxiolytic dose of diazepam (0.08 mg/kg) did not affect this behaviour. Taken together, the present results suggest that the essential oil from Tagetes minuta L. may exert a negative modulation on the GABAergic function without affecting the learning ability.

Lateralization in chicks and hens: new evidence for control of response by the right eye system

Domestic chicks show marked lateralization of visually evoked behaviour: left eye use is associated with, and has advantage for, the detection of novelty; right eye use is associated with the use of selected cues to determine what response should be given. Experiments undertaken to see how far such lateralization might be a transient feature of development showed similar patterns in both adults and chicks: (i) use of the right, but not the left, frontal field allowed the inhibition of pecks at a familiar social partner; (ii) in distant viewing, there was spontaneous preference for more use of the left eye when the social partner was familiar rather than unfamiliar. The chick data, in particular, support the hypothesis that the visual system fed by the right eye is especially competent in the control of response. This is shown by the ability of birds that are using the right eye to inhibit approach to an entirely novel potential social partner, and inhibit pecks at a familiar partner. The resemblances between chick and hen are sufficient to show that the basic adult pattern is already present in the young chick: the various developmental changes in features of lateralization, such as days of bias to control by one or other hemisphere, thus do not cause the appearance of the adult pattern.

The behavior of the Japanese or domestic quail Coturnix japonica

This paper reviews the literature pertaining to the behavior of the Japanese or domestic quail Coturnix japonica. Details are given of the classification, characteristics, domestication and the economic and research potential of the species. Further sections deal with sensation and perception (including taste and smell, vision and hearing), maintenance behavior (including feeding and drinking, dust bathing and thermoregulation), development and aging (including vocalization, filial imprinting, sexual imprinting, fear and avoidance responses, sexual maturation and aging), adult learning (including habituation, instrumental conditioning, Pavlovian conditioning and observational learning), photoperiodism, reproductive behavior (including courtship and mating, hormonal control and ontogeny of sexual differentiation, and male and female sexual behavior), parental behavior (including nest-site selection and nest building, incubation behavior and its hormonal control, and hen-chick relationships), and aggressive behavior and dominance (including agonistic behavior and the hormonal control of aggressive behavior).