How old do the chicks need to be before I let them roam with the big girls? Been raising chickens for a while but never tried to integrate new chicks into an existing flock. The two older hens I've had 6-7 years and the six newbies I got as day olds about 6 weeks ago. The older girls free range during the day as the little ones will after integration.The little ones were brooded in my chicken house that contains the coop itself. The building I call the chicken house is 16x 32 feet. The coop itself is 7x16 feet. Older hens have had access to meeting the little ones while in their brooder inside the chicken house. About the past week I've setup a temporary run for the little ones outside where the older ladies can have more contact while keeping them separated. Seems to be going well with the older ones ignoring the youngsters.