ouch !!!
this happened to my favorite hen, CT, ( crooked toes) who was the sole survivor of a fox attack that took 24 of 25 of her house mates. CT was very traumatized by that, so we brought her indoors, for almost a month until the goats arrived, and then she determined to stay with them. After we replinished our poultry srock, she grumpily went back to the hen house. I had not clipped her wing so she could still go visit with Lucy & Ethel ( the nubians) My husband found her one afternoon when he came in from the field, lying on the barn floor, gaping feathers gone, and torn from wings to head, all the skin on her back. I could see muscle . I cleaned her with normal saline, and appiled neosporin ointment, and tried to bandage, put she kept pulling it off. I finally put a stretchy net over her, and she healed slowly, but surely. She laid for the first time yesterday since this happened in May. Now, no matter what , the dog stays tied, he's too hyper.
Good luck
Tressia