OK.........I have a large coop and a 4x8 tractor with a second floor. In the large coop that is divided, I had 4 BRs and 2 RIRs on one side. They all get along. Rocky the roo keeps them all in line and is a good roo. On the other side of the coop I had 3 RIRs - 2 roos and a pullet about 12 weeks old. In the tractor I have 2 BOs about 16-17 weeks. They are as big as the RIRs in the big coop, but just a little smaller than the BRs. I thought that I would go ahead and introduce the BOs into the big flock and slipped them in there one night. Mistake. The BR hens literally were beating them up. That morning I had to go and rescue them. So, I got rid of the 2 small RIR roos and took the pullet and put her in with the BOs in the tractor. A couple of days and they had it all worked out. Everyday I let the big ones free range. So yesterday I opened the door on the tractor and let them out to free range with the big girls. Now everybody gets along. Go figure. But the Bos and the one little RIR go back to the tractor to roost. Crazy chickens!