Was very worried about putting them in the coup with my two older chickens. The first couple times, I put the older ones, out to run in the yard, and let the chicks in the coup so they could see each other and still be safe. My rooster is lame, and was never a threat, but the older hen is definitely the queen. She tried to peck them through the wire. After doing that a couple days, I put them in together. The hen ran at the chicks and they would run to the other side of the pen, but after 2 or 3 times she stopped. They have been in there together for about a week and they worked it all out just fine. At 6 weeks they are bigger than I thought they would be.