This may not be an option, but we had friends that put their mean leghorn rooster in a pen of bantam roosters for a day or so. He's now the most timid rooster I've ever seen! I know this one, because we have recently acquired him. He's the most timid rooster I've ever seen. We also got one of their bantams, so it will be interesting to see how the leghorn reacts when the bantam is no longer around.