Yes, maybe that is true. I have many roosters and hens together. When I add new hens there is never any problem after just a few pecks and short chases from some of the more dominant hens.
When I add new roosters they will fight with the other roosters, one at a time, and again 99 percent of the time the fight is over in a few minutes and they all know where they are.
I allow lots of space in a huge run, with lost of pots, baskets and logs, potted trees, etc, so there is always places new ones can hide to take a break if they need to.