We had a good-sized existing coop with not many hens, when we ordered 24 baby chicks last spring. Three did not survive. We brooded the survivors is our well house in a brooder with a heat lamp. It worked out well. There came a time when we needed to move them outside so we put up a grow-out pen adjacent to the older girls' pen where they could "see but not touch" each other. It was made of panels of chain-link fencing and was originally a dog kennel, but worked great. We also got a kind of plastic storage shed for theor coop.
They no longer needed heat by this time but we left them a little night-light. Their food was separate, no layer food for them! We provided grit in a separate dish.
After a month I combined their food with the big girls' all flock and there was also oyster shell in adddition to the grit although they were a month away from laying yet. I left the gate open between the two pens. It took several days before they realized they could explore each other's digs, but there were no problems, they integrated just fine. And now I have one big flock, so yahoo!
They no longer needed heat by this time but we left them a little night-light. Their food was separate, no layer food for them! We provided grit in a separate dish.
After a month I combined their food with the big girls' all flock and there was also oyster shell in adddition to the grit although they were a month away from laying yet. I left the gate open between the two pens. It took several days before they realized they could explore each other's digs, but there were no problems, they integrated just fine. And now I have one big flock, so yahoo!