Some of our roosters are brothers, so that makes it easier cause they grew up together and just establish their own pecking order. In the other cases, we have the new roos isolated at first; then, after that, we put them in a pen where the other roos can see em, and communicate with them through the bars, but they can't do any serious damage; they start the pecking order that way. It is funny to watch them puffing up at each other and pulling grass, while the hens stand around admiringly. After a week or two of that, we let the new roo out and we just hang out with the flock for a while, and off and on for the next few days, to see how they interact; usually they have no problem establishing a peaceable pecking order with no bloodshed, and, in fact, it is neat to watch the roos divide up the hens, and communicate with each other about predators and other stuff chickens talk about, I guess. They are all free range, so they have lots of room to spread out if they want to, too.
