Place the brooder in the coop. Take one side off and make an opening about 4" wide that a full size hen can not fit through. Bed it than cover it. Attach a small pen out of chicken wire and put their food and water there. They will sleep in their little chicken house and it will stay warmer than the coop. They have a play and socialization area that will work until you combine the groups. I've mixed mine this way by about 10 weeks. I leave the brooder in the coop as a type of safe house. They can run in there to get away from the hens plus most chicks will continue to sleep on the floor until they are about 16 weeks. Once they move up to the roosts at night, I take it out.