Social buffering in domestic hens, Gallus gallus domesticus: breed differences in reliance on conspecifics and humans

Domestication has profoundly altered human–animal interactions, allowing social buffering to extend beyond conspecifics to include humans in several domestic species. However, breed-level selection represents a more recent and understudied layer of domestication that may shape how animals perceive and respond to humans. To investigate how contrasting selection histories influence animals’ perception of humans, here, we compared two laying hen breeds: White Leghorns (commercial breed), intensively selected for productivity, and Fayoumis (Egyptian heritage breed), shaped by both natural and artificial selection. Birds were tested in a separation–reunion paradigm involving two brief (3 min) phases of social isolation in a novel environment, each followed by a 3 min reunion with either a conspecific or a human. Calm behaviours (e.g. exploration, foraging, reduced vigilance), locomotion and proximity-seeking behaviours (i.e. time spent near the social cue) were recorded as behavioural indicators of social buffering. At 12 weeks of age, birds were reunited with a familiar conspecific or a familiar human, and at 18 weeks with a familiar versus unfamiliar human. White Leghorns seemed to respond more strongly to social cues from both conspecifics and humans, showing calmer behaviour during reunions compared with separation phases (social isolation). White Leghorns also exhibited higher locomotor activity, particularly during separation. In contrast, Fayoumis showed fewer behavioural changes across test phases, suggesting a more socially independent behavioural strategy. While both breeds spent similar time near conspecifics, White Leghorns spent significantly more time in proximity to humans, irrespective of familiarity. These findings suggest that breed background and history may shape how chickens use social partners for stress regulation, highlighting the broader role of selective breeding in shaping sociocognitive responsiveness to humans and its consequences for human–animal relationships and welfare across domestic species.