Piling behaviour in Swiss layer flocks: Description and related factors

Smothering is a major concern within the Swiss layer industry as it can lead to high number of animal losses. The underlying cause piling behaviour (PB), phenomenon where hens densely cluster together in litter area. aim this study was describe PB and events preceding PB. Furthermore, we investigated relation piles, pile duration, involved with time day, flock colour, age, environmental factors, responses tests. We video recorded corners areas (floor) inside barn winter garden 13 commercial flocks (5 white, 5 brown, 3 mixed hybrids), which were known previously experienced problems smothering. data (air speed, spot temperature) observed assessed flock-level two tests (novel object test, stationary person test). From recordings, characteristics at 20 30 weeks age (w) three times per day (0?5 h, >5-10 >10?15 h after lights on). Statistical analyses included generalized linear mixed-effects models Spearman correlations. Results showed that mainly preceded by single hen activities (77.9%) non- hysterical mass movements (7.6%). More piles largest numbers animals occurred white brown >5?10 came on. lower duration higher w compared w. No correlation found between factors test characteristics. Potential causes for are numerous, though provide discuss likely mechanisms, including response facilitation, individual stimulus response, anti-predation behaviour, based on our findings. could relate diurnal behaviours, example, dustbathing laying floor eggs