Today my younger chicks (9 weeks) free ranged again with the older chickens (24 weeks) and all was good. They've seen each other and free ranged together for the last couple months. So, we got home after dark to find ALL the chickens in one of the coops. I removed the younger girls and put them back in their own coop for the night. The coops are really supposed to be for three to four girls. I'll probably have to move them each evening. Is this a mistake? I kinda thought they'd spread out a few to a coop at bedtime or the younger ones wouldn't be allowed in with the bigger ones.