I have a flock of 12 Rhode Island Reds and these girls are totally mean to my one Cochin and two Black Copper Marans. So much so, that I have to let the RIRs out of the pen in order for the others to be able to eat or drink. They all roost peaceably together at night, but daytime is for fighting. I finally purchased a smaller coop and fenced off a separate area for the the Cochin and Marans (I also have two Cochin chicks that will go in with them when their feathers come in). Once they were in it, however, they seemed unsettled and freaked out. The Marans kept trying to get back to their original side and the Cochin managed to get out (for the first time). Is it usual for chickens to dislike change? Is it better to leave them in their original situation rather than try to create a new one? No one is being hurt, it just takes a lot of management on my part to ensure that they all get fed and watered.