It can depend on the individual roosters, but generally 10-15 hens a rooster is supposed to spread out the mating. Sometimes a rooster will pick an easy submissive hen and just mate her constantly so numbers don't matter with that type of rooster.
I generally start weeding out the...
He should heal up now that he's separated. Unfortunately that happens with hormonal roosters. What are your plans for all the roosters? Some can get along and others won't.