Yeah, I'm pretty new to this myself but I do know that chickens will go after wounds if they see them.  My husband learned that the hard way.  lolololol  He has a cut on his ankle and those pesky chickens won't leave it alone!  And, don't go into the coop with red or pink toenails or fingernails... same idea.  My chickens always go after this white ring I like to wear... it's a big white plastic flower.  I make sure to take it off before I go outside and visit with them.
So, if your rooster wounded her even slightly, the other hens would see the wound and keep pecking at it.  You can try some Blu Kote (I think that's how you spell it)... you spray/paint this over the wound and the other chickens won't mess with it so it can heal.  Check your hens every once in a while to look for any wounds or keep an eye out for pecking and have that stuff handy.
Also, from reading these forums I've found that chickens can survive a LOT of damage.  Look through the emergencies forum and you'll see chickens that have been completely scalped or lost a wing or a leg and survived.  They're tough birds so try to give them a chance to heal even if it doesn't look like they could possibly survive something.
Good Luck!!
5Leepy!