Same started happening with one on my laying hens. I isolated her too. Any help will be appreciated. I am in upstate NY and this started happening when it became really cold. They are 8 in number, confined in a 4x8 coop + 8x16 attached run when it is snow around and below freezing. This doesn't happen when I let them roam free in the yard (temperature in high 30s with not much windchill. Interestingly, it has not harmed the weakest/smallest of the group, and the rogue one happens to be the biggest/strongest. Btw, I put turmeric powder as a natural healing/antibiotic for the wounds.