Hi @Robert G :frow Welcome to BYC
The only solution to overmating like this is to separate, rehome or cull one of the roosters. Tag teaming a hen will eventually wear her down - not only her feathers, but physically and mentally. Being run ragged by 2males, she is most likely not eating and...
Yep, that's from mating:)
Saddles do offer some protection from the nails and spurs, but the feathers underneath will still get worn and broken. Inspect under the saddle at least once a week for any abrasions/weakened or broken skin. Even with a saddle, he will mate her A LOT since she is...
Being cooped up;) could be partially the problem. Getting more girls may help, but a youngster is going to still mate very frequently and they do tend to have their favorite girl(s) that get it more than the others. Usually a lower in pecking order girl, but not always.
Do you have any photos?
I am also thinking that your boy is 9months as well? Cockerels are filled with hormones, so you can expect more of where that came from, especially when the weather warms and spring arrives.
You have a few options:
find a saddle with wing protectors - this may help...