I was thinking the same thing Skip. I had no idea what caused this issue nor the swelling. I wanted pictures to show others and hung around the vets office so we could talk about what he found. I did know it wasn't from bedding, at least from here. All ours are kept on either newspaper or paper towels and he hadn't ate the entire time he was here. I did forget to mention that the spot had became necrotic but from the outside you couldn't tell.