I have 5 roosters free ranging with my flock- 1 Buff Orp, 1 Splash Orp, 1 EE, 1 D'uccle and 1 Silkie. They are out with 20 hens/pullets and about 8 half grown chicks. They don't seem to have problems getting along. I took my time introducing them all so that I wouldn't have to keep them in 6 different breeding pens for winter. There is definitely an alpha but he doesn't try to kill the others- just keeps them from breeding.