We refurbished our children's playhouse into a chicken coop. It's been working great...15 chicks in an 8x8 coop. The five 5 week olds still nestle on the ground, the older ones use the roost. DH built the nesting boxes seperately, and they are painted and ready to be in place. How soon should they be in place? The oldest are about 13 weeks old, then a group of 8 week olds, then the 5 week olds. I don't want the younger ones using it as a bed time spot, but want to be ready for the big girls. Any suggestions?