Abstract
Understanding chicken cognition is essential for improving welfare in production systems, as it reveals how animals perceive and respond to their environment. Barren housing can compromise welfare, including negative affective states and cognitive deficits, but previous research mostly focused on effects of barren environments on young animals. Here, we investigated whether hens moved to battery cages once adults show lower cognitive performance than those kept cage-free. Because stable inter-individual differences (personality traits) can modulate how animals respond to environmental changes, we also explored whether personality modulates this effect. Sixty hens were reared in enriched aviary pens; at 18 weeks, half were transferred to battery cages (456 cm² per hen) and the rest remained cage-free (5,333 cm² per hen) for 64 days before testing. Personality was assessed through four standardised tests, and spatial memory was evaluated with a modified hole-board task. Working memory (WM), general working memory (GWM), and reference memory (RM) were calculated from visit ratios. Behaviours after birds consumed all baited rewards were recorded to assess responses to reward omission (e.g. extinction learning). Battery hens outperformed cage-free hens in all memory metrics and were more active during the post-reward period, showing more empty-cup visits. While the enhanced memory performance of battery hens is likely driven by increased reward motivation and greater engagement with the task, our results also suggest these birds showed a deficit in extinction learning. Personality also influenced performance: more fearful hens had lower WM and GWM and were slower to find baited cups. Housing and personality jointly shaped cognition in laying hens, highlighting that enhanced performance under poor conditions may not indicate better welfare, but rather a shift in motivation for food rewards.