Bobbi-J offered some really good advice! My only advice to add would be to go ahead an put the young roosters (or the one you want to keep - I'd get rid of the other one) in with the older hens. Nature has a way of teaching young cockerels manners and older hens are just the ones to do it! The cockerel will probably lose a few feathers and take a few beatings, but he'll learn that not all the ladies are easy and he'll have to work to gain their respect. A difference in age of even a few months will help with this if the hens are older. The pullets are not sexually mature yet, and so they are not the least bit interested in what your teenage roosters are trying to offer! When they begin doing the egg squat, they'll be a bit more interested.