The guy who boards my friends' horse has a duck, I think a pekin. His son gave it to him for thanksgiving dinner one year, but he couldn't kill it so he ended up just keeping it. Anyway, the duck, Donald, does not have any duck friends, and had bonded rather strongly with the horses. My friend has noticed that Donald has been limping, and has some black stuff on his leg. She could not get a closer look because they couldn't catch him. If they do catch him, there is a strong possibility that I'll adopt him. We do not have any horses, but I do have three khaki campbells. If I do adopt Donald, what should I do about the frostbite, and introducing him to my ducks?