| Re: nipping himself?
Have you checked him for fleas? The rear end is a favorite parking place for fleas. Pick up a flea comb and go over him with it and see what you find. My dog will start to scratch and chew if she has only one flea on her!
As for the shaking, the way you describe it concerns me, but we can't see it. I think a vet should be consulted. |