I have 2 girls that are 6 weeks old and they are out in the coop now. They prefer it to the smaller box they were in. They get cold before bed and make their silly sound to indicate their desire to sleep and be warm. If they didn't go in the coop on their own I shoo them in and turn on a light for them. I will keep a light in there until all the babies are grown enough to be in there and used to being together. The coop is a bit big for the 5 I have at the moment and I think now that it's bigger they get a bit scared, but the light helps.