You could take a wait and see approach, but even if the roos get along they'll overmate the hens. You don't have to butcher them, you could try finding some of the boys new homes. The younger you find them new homes the better IMO.
If the alpha roo is very dominant over the other roos he will do the majority of the mating, but boys will be boys and when the others mature they will try every time they think they can get away with it.
Missing feathers, mostly. When I first got my hens i had three roosters, and they would gang bang the hens, they all lost most of their back feathers in the few weeks before we gave away the extra two roosters. the feathers are starting to grow back on most of the hens now that it's growing cool, but I have a couple that I still don't see new feathers on yet. I may have to give the poor girls a sweater. lol