12 yrs of raising chickens and never seen anything like this. Started of with wounds on one birds feet. We were puzzled. Treated her and kepted a close eye out for a disease out break. Then over 20 birds were getting massive holes on the tops of their feet. We scrubbed their feet and legs and treated them with topical and oral meds and antiseptic but the problem kept manifesting. We have over 70 chickens so we were freaking out. I visited the big coop one morning about 3 a.m. and found big rats on the roosts eating away on the chickens while they were sleeping!!! My god it was terrible. The damage they caused was inconceivable. They even chewed a spur off our beautiful red rooster. I have since rat proofed the big house (as much as possible) and placed several live traps. As well as bait containers and still going out late night to monitor. Never a dull moment in the life of a farmer. We have breeding houses in touched by the rats... knock on wood I suppose. I wish I could sleep as solid as a chicken sometimes.