Beyond physical and zootechnical characteristics, the process of animal domestication has also altered how domesticated individuals, compared to their wild counterparts, perceive, process, and interact with their environment. Little is known, however, on whether and how domestication altered the perception of conspecific calls on both domesticated and wild breeds. In the present work, we compared the vigilance behavior of domestic and captive-born wild fowl following the playback of chicken alarm calls and contentment calls (control). The playback tests were performed on four different breeds/lines. We first compared the behavioral reaction of domesticated White Leghorn (WL, a breed selected for egg production) and Red Junglefowl (RJF) hens (ancestor of domestic chickens). We also compared the behavior of Red Junglefowl hens selected for high or low fear of humans (RJF HF and RJF LF, respectively), a proxy to investigate early effects of domestication. Contrary to our expectations, no breed/line reacted accordingly to the calls, as the increase in vigilance behavior after the playback calls was similar for both alarm and contentment calls. Although no call discrimination differences were found, breeds did differ on how they reacted/habituated to the calls. Overall, WL were more vigilant than RJF, and birds from the RJF LF line decreased their vigilance over testing days, while this was not the case for the RJF HF line. These results suggest that birds under commercial-like conditions are unable to discriminate between alarm and contentment calls. Interestingly, domestication and selection for low fear of humans may have altered how birds react to vocal stimuli. It is important to consider that farmed animals may interpret and be affected by the vocalizations of their conspecifics in unexpected ways, which warrants further investigation.

Play is common in young homeotherm animals and has an important role as a tentative indicator of positive states of welfare. Furthermore, during domestication play is believed to have increased in frequency in several species as part of the domestication syndrome. Here, we studied the ontogeny of play in chickens in two experiments. The first compared the behavioural development between domesticated White Leghorn (WL) laying hen chicks and ancestral Red Junglefowl (RJF) and the second compared the same between WL chicks that had experienced the stress of commercial hatchery routines and a control group, hatched under calm conditions. In both experiments, 10 groups of four chicks each from each of the groups were moved twice per week to an enriched and fully enclosed play arena, starting at day 8 and finishing day 39 or 53 after hatch. In the arena, the frequency of play behaviours was recorded during 30 min and divided into object, locomotory and social play. In experiment one, total play as well as object play was significantly more common in WL whereas locomotor and social play was more common in RJF. In experiment two, total play was significantly more frequent in commercially hatched chicks, despite that none of the sub-categories differed significantly between the groups. In conclusion, domestication as well as early stress does affect the occurrence of play in chickens, but the effects are complex and require further research.

Prosocial behaviour is pronounced in humans and prevalent in some non-human animals, however, the occurrence of the trait in chickens has not yet been investigated. Here, we studied the occurrence of prosociality in four different lines of adult female chickens. To explore the effects of domestication, chickens of the domesticated layer White Leghorn (WL) and the ancestral Red Junglefowl (RJF) were compared. Additionally, to explore the role of tameness, Red Junglefowl selected for high (RJF HF), or low (RJF LF) fear of humans were also studied. The hens were all tested in a prosocial choice task adapted from a previous study conducted on rats. Each individual was first trained to differentiate between a compartment where itself and a companion received food treats simultaneously (representing a prosocial choice), and one where only itself received the treat. Following training, each bird was tested in a free-choice set-up. No occurrence of prosociality was found at group level in any of the lines, however, our results suggest that the trait may occur in some individuals, and that domestication and increased tameness may have increased its prevalence, although alternative explanations such as side bias and social competition cannot be ruled out. Since this study is the first of its kind, further research is required to make any definite conclusions.