Yes. Not only would you risk stress and possible feather damage from over-matings but the males most likely would fight for top dog status and the right to the hens. And that could be very rough, if not deadly. I just wouldn't advise it. I'd choose the one that I liked the most and with the best personality but that is just me. Best of luck to you!So I know the general rule is around 6-10 hens per rooster but I have 3 young cockerels and 13 hens. Will this be a problem?