We have recently been given 3 fairly elderly chickens (2 Marrans and 1 Light Sussex) as their owners are out of the country for quite a while. We have a coup with 3 nest boxes which is inside a run of about 6m x 3m.

So far only 1 of the Marrans has been laying (the Sussex hasn't been laying for a couple of years now apparently so we think she has gone into retirement). We would like to have some additional chickens (ex battery) but are concerned that it will upset the existing girls, is this likely and if not how many would be reasonable in this kind of space?