My youngest babies were hen raised in a section of the coop. Everyone else free ranged all day and came into their side of the coop to roost at night. When I started letting the little ones and momma go outside, the big kids did show mild aggression toward them. One hen in particular was bossy. I played mediator a few times, stomping in front of her if she got mean. I don't have a run and they have plenty of space to form their own little cliques. Everyone seems to get along fine and share the whole coop now.
When I introduce new birds to my "homies" I keep them in a dog crate for a few days and place it in the common area. The "homies" check them out and even try to peck them through the cage, but the "newbies" are safe. When there's no obvious sign of bossiness, I let the newbies out with supervision. (Yes after several days of quarentine, first.)
Every situation is different. Every little chicken brain is different. Just pretend you're a kindergarten teacher. Do whatever makes sense for you and your critters at that moment.
When I introduce new birds to my "homies" I keep them in a dog crate for a few days and place it in the common area. The "homies" check them out and even try to peck them through the cage, but the "newbies" are safe. When there's no obvious sign of bossiness, I let the newbies out with supervision. (Yes after several days of quarentine, first.)
Every situation is different. Every little chicken brain is different. Just pretend you're a kindergarten teacher. Do whatever makes sense for you and your critters at that moment.