Googoo, our BR, was degloved down her whole back this summer by our dog. Miraculously, she made it through and laid her first egg last week and is back to bossing everyone around. We cleaned her wound with diluted Betadine, coated it with Neosporin (no pain reliever type), then switched to nothing but Blukote once we realized she was pecking her wound. We kept her isolated for two weeks in a dog crate, until the wound dried out a bit and she was seeming peppier. We kept her in the basement (stinky) and softened her food, gave her scrambled eggs, etc.Blukote was critical--without it she would have been mauled by the others. I put it on her morning and night. When we reintroduced her to be others, we put the dog crate in the coop for a couple of days before we let her loose with the others. They seemed really happy to see her.
So obviously she had no internal injuries, despite the outrageousness of her wound. I still can't believe she made it. Sadly, Larry our BO hen was killed by the dog--a much smaller wound, but she must have had internal bleeding: she didn't make it through the first night, poor thing.
We're still struggling with the dog. She went to boot camp for training, and we're working with her -- she won't even look at the chickens now. But she's got other issues, too. Long story. We might rehome her despite her improvement.
Good luck with your bird! I hope she didn't get crushed inside. If she didn't, she's got a good shot! I'm glad we tried to help Googoo--I almost out her out of misery the minute I found her staggering around the yard. She was lucky!