It really did not have anything to do with being separated from the hens, they just came into their own, hormones are and were flying, and they can become more and more aggressive. Aggressive toward each other, aggressive toward hens, and aggressive toward people. If you had not separated them, your pullets would most likely be ran ragged, and could be dead.
But if you want to grow up some pullets for these boys, do wait until the pullets are laying eggs, before introducing them to a rooster. I would go with sexed hatchery chicks, or you are going to be right back in this situation.You are at least 5 months from growing up chicks to be ready for a rooster. Do you think the bachelor pair will get along well enough to wait for that?
Post some pictures of your set up, of your birds. I would suggest contacting your county extension agent, or 4-H groups. Sometimes someone knows someone who wants a rooster to be a rooster.
Mrs K