I have 2 leghorns and 2 barred rock that are 12 weeks old. They are still in the brooder but its getting pretty cramped. In the big coop I have 3 RIR 7 silkies. The babies are fully feathered and the temp is down to 65 degrees. We live in Michigan so its going to get cold soon, having a indian summer right now. I have a covered run and heated Coop. Can I added them in the coop or are they still to small to add to the flock and they will be pecked to death. I just do not want to invest in a x pen for such a short period of time and the brooder is starting to smell in the garage. Help Please.