Space use at night and social relationship between roosting partners in a large flock of laying hens.

1. Laying hens in two aviary flocks of 1250 females and 12 males were investigated to determine if hens used the same roosting site more often than expected by chance and whether hens that roost next to each other for two consecutive nights (close groups) had fewer agonistic interactions than hens roosting far away from each other (distant groups) when put into a new environment in groups of 4 birds. 2. Hens showed a significant preference for using the same roosting site on consecutive nights. There was no difference between close groups and distant groups in agonistic interactions. However, in close but not distant groups, a low or high level of interaction on day 1 predicted a low or high level on day 2 that might reflect established relationships in the close groups. 3. It was concluded that hens prefer the same roosting site in the short term but further research is needed to investigate whether hens roosting next to each other recognise roosting partners or not.