Ahh..so size difference.I will only be using the New Hampshire for crosses. I was just wondering if anyone had any experience with keeping these roosters in a mixed flock with smaller (but still standard) sized birds. I am not opposed to keeping him separate and breeding him when necessary, I just like to have a game plan, and hate having to build things at the last minute. I like to learn from other peoples experiences as much as possible. Perhaps the size difference is not enough to be a problem. I keep my Phoenix's separate because of the size difference and pecking. I try to keep their feathers nice to show.
I have a large Welsummer cockbird, and used to have a large Dk. Brahma mix.
Both are/were mellow and agile boys, never had any trouble/injuries with them mounting the slimmer girls(EE and hybrid crosses).
Might depend on his technique and the possible 'competition aggression'.....but I've never had more than one active male on the premises for long.