My 2 runs are side by side, so the two groups were used to seeing one another on a daily basis. As I recall, my youngsters were about 6 months when I integrated them, and about the same size as the adult hens. The boss hen aggravated them for a day or two, & a couple of them had to roost in the run rather than the coop for a while, but they managed to sort things out with no bloodshed & they're all just one big happy family nowHow old do chicks from a brooder need to be before you can put a cock in with them, or let them out with the cock and adult hens to be more precise? I have them in the second side of a divided coop and run setup (there is a door between the two coop sections and another in the run part). It can be one big or two smaller coops and runs. I built it for breeding groups in the future that are all together in the winter.