Hi, We've had the same group of 5 chickens for over 1 year and all of the sudden one of the chickens will not join the others to roost in the coop at night. She is perched at the door to the coop when I go to close it and won't let me close the door all the way. She's there again in the morning when I go to open the coop. Any thoughts/ advice? Thanks!
Check her for mites after dark. There may be mites lurking in the seams of the coop roosts and walls that only come out at night. There also could be rats that bother her in the coop at night. She also could be bullied at night. I had trouble with chickens wanting to roost on my inner screen door to the coop, so I had to keep it closed and just leave the pop dor open so they would be forced to get on roosts.