Do hens have friends?

Chickens do not appear to make friends even if kept in small groups

Source: S.M. Abeyesinghe, J.A. Drewe, L. Asher, C.M. Wathes, L.M. Collins. (2013) Do hens have friends?
Applied Animal Behaviour Science, Volume 143, Issue 1, Pages 61–66 January 15, 2013

People are interested in the extent to which ‘friendships’ can improve the welfare of farm animals , so this experiment looked at small groups of chickens to see if they were choosy about which individual chicken they spent time with. Eight pens with 15 pullets in each were observed for eight weeks. The hens were all 15-weeks-old at the start of the experiment, Hyline-brown domesticated layers, and had been reared in a floor system in a house containing 20,000 chickens. The focus was on what the pullets did during daytime activities, and how they roosted in the evening. Their behaviour was recorded by CCTV cameras, and analysed to see whether the hens spent more time together than would be likely by chance .

The pullets showed little aggression with one another, which may be because they were able to set up stable social groups as they acclimatized. They did not appear to be choosy about their companions, either in terms of where they went, or which chicken they were close to, nor were they particularly choosy about where they roosted. Most couple combinations never perched together at night. Some couples did apparently often perch together, and there was possible evidence of preferences for two couples in daytime location in one of the eight pens, though this may not be important given the low numbers. In general , it appears that hens are not choosy about their companions, either when they are active, or when they are resting, even when they are in a group that is small enough for them to get to know one another.

The behaviour of these pullets may have been affected by their having been raised in a large flock, since it may make sense to be socially tolerant of all other chickens in a large group, rather than focusing on individual companions. Chickens also learn social rules from their mothers. It is worth studying chickens raised by their mothers in small groups to see whether they behave differently, and to study the behaviour of the ancestor of chickens, the Red Junglefowl, to see whether the unimportance of friendship is a trait found in chickens’ ancestors.