I have three chickens that are just over a year old. They have been out in their coop and 'putting themselves to bed' (going into their coop on their own at dusk) since last summer. But for the last week they have not been going in, but trying to sleep on top of the coop roof. So each night instead of just closing the door, I need to pick each of them up and put them in the coop. I have checked for bugs (although I'm not really sure what I'm looking for), changed the bedding and checked for anything 'scary'. What else might be making them do this? Will they get over it if I keep putting them in? My run is not secure for nightime, so I can't leave them out. But it really sucks to be out there in the dark every night!