The way I use is a slow introduction. A separate sleeping area partitioned off from the others in the coop. The new arrivals stay in the partitioned area for a week or more so the they can get to know and be known by the flock, through the wire. After the introduction period leave them free range with the others, while still having their own sleeping area. Have at least two feeding and water stations during the free range as there can be some bullying. The old and the new may take a while to hang together, but as long as they aren't trying to kill each other. it is normal.
