I've had a few bullies, and I'll usually put them with the cows for a few weeks to a months.. if you're doing it with several, let the least of the bullies back in with the rest one at a time, the rest will gang up on them and teach them manners again, progressively let the bigger ones back in (a few days between each) and the pecking order will change...
Last year I had one that was really bad, she went from being top cow to 2nd from last (out of 4).. The two more dominant ones now aren't a problem, they will make their place if need be, but don't stir the pot like that one used to.