Hope someone has a good answer for you.
My little jap roo is the alpha, and these days he doesn't slip with the other roos, keeping them from the treats and not allowing any challenging behavior, and watching everyone eat, etc.
And all my roos know what hens are for ... they are only 3 months old. (I'm not so sure they know how to be effective, but they have the general idea.)
However, even though the jap roo really stays on top of his "alpha" duties where keeping everyone in line is concerned, the hens DO sometimes grab a feather or peck him here and there. And he would NEVER stand for that from the other roos, but he accepts it from the hens.
I've been wondering about that myself. I'm guessing it's not a dominance thing with him and the hens, or else I think he would fight them. He does usually stop them fighting each other, and will chastise the hens when he thinks they've done something he doesn't like. But he lets them pick on him a little.
Hope someone can answer on this.
trish