With that many hens and two roos, I'd guess that the roos are competitively mounting hens resulting in the hens losing feathers on their backs due to excessive mounting.
You can get rid of the most agressive roo, if you don't want to do that, simply take duct tape and make "saddles" on the hens backs so the roos claws can't hurt the hens. As the feathers grow back the duct tape will eventually fall off. Keep up with the taping though, until the hens have sufficient feather growth.
The two roos will argue and fight over who is the top dog and what happens is that since they can't really punch each other out, the sub dominant roo will immediately mount a hen that the dominant roo has just mounted. Consequently your hens are suffering feather loss to a high degree.
You can try trimming the roos claws some but that really doesn't work that well since the behavior still happens....
Best bet is the "saddle " thing....
We've had several flocks, with as many as four roos but have finally decided to raise hens without roos around. The constant crowing all night long and the fighting with each other and the hens losing feathers constantly were just too much for us to handle so we gave them away to our local feed store. Granted, the roos are beautiful things to behold but the behavior may not be what you want for a peaceful flock.
