ive had the chicks in with adults for a couple weeks. yesterday I caught the hens chasing one of them mercilessly. first time. this morning this morning I found pieces of one inside the coop. and a whole on by the fence with just the head gone. head seemed to be missing on the one found inside as well. there heads do fit through the fence. I don't know if the adults killed the little ones or if something got them from outside and then the adults dragged it inside and ate it. the little ones are about 9-10 weeks old and had no problems in the coop for a couple weeks. if picked on they hide under the nesting boxes where they cant be reached. really bummed out!!!