Oh, poor dears.
Yes, they should be fine, though some may not regrow their feathers all the way.
Look them over closely. They might have been plucking each other from stress, but they might also have mites. If they have mites, they'll need treatment with something strong- NOT diatomaceous earth, it's bad for bird lungs and nowhere near effective enough to get rid of an infestation.
Do you know how to care for coturnix? They're not difficult birds, the hardest part is predator-proofing. These will probably need a lot more protection from the wind than usual until they grow their feathers back.
For now, give them as much space as you can, and be sure they have lots of places to hide. Quail like to hide under brush- fake Christmas tree branches are great for that. They'll do best if you can surround the cage partially in something solid, a foot tall or so, to give them the illusion of cover. Give them sandboxes, too, the poor dears have probably never been able to dust bathe.
I'd start trying to sex them. Males will fight, so you should only have one male per pen. If you don't intend to have more than one quail pen, the kindest thing to do is cull the extra males now before they start fighting again. You might not have any males if the person who abused them like that was keeping them for the eggs, but if you do have too many males, it's best to weed them out now.