Hmmm.... hard to say what's at play there.
It could have something to do with the cockerel/pullet ratio.
It could just be a pecking order thing, but I find it a bit strange that the alpha cockerel is scuffling with her.
I wonder if she is not submitting to the alpha, maybe she's aligned with the beta so the alpha is miffed.
You could try adding another roost slightly lower than the main roost.
You could try isolating the one of the cockerels and see if how changes the dynamics of the flock,
but that could cause problems upon re-introduction of the isolated cockerel.
I would strongly suggest you get rid of one, or both, of the cockerels.
They are lovely to have around, and often multiple males can work out, but it can cause problems in flock dynamic.
It's much easier to add an adult cockbird or another cockerel to the flock down the road than it is to sort your current problem.
It's really best to keep as few males as you need for reproduction in a flock....
.....or keep separate flocks in separate coops.
Sometimes they can free range all together if they have separate coops or a large enough coop and they work out the pecking order.
Tho a few folks with experience in managing them have kept multiple males.
Just a few thoughts.
Edited by aart - 10/5/15 at 4:36am