I kind of threw that out there quick, while in my truck getting ready to go into work, but it's been my experience. If you had a mature rooster and ideally some older hens to keep the young guy in line it's not bad, but introducing an older cockerel/ young rooster to same age females in spring is not ideal. It's been mentioned on here often and I know it's not the situation that you're in, but to keep an only female flock for a few years before adding a cockerel (or for that matter to add an older, mature rooster and skip the young phase). Either approach is less stressful for all involved. That doesn't help you much now, but file it away for later. You can try picking the less dominant of them and integrating him now. If that works out get rid of the other and then hope things go smooth in the spring or just rock the bachelor pad for a year and then revisit your options and try integrating then. Or lose both and wait till next spring and add a few young pullets and a cockerel to the existing flock and let them grow up with the older hens to keep them in line. There ARE options, but try and pick one that's as easy on you and your birds as possible.