It is now 2016 and I have a shepherd doing the same thing. She is a rescue dog and when we found her she had a broken tail and the tip of her tail was chewed off--plus she was missing all of the hair on her tail and backside. She did a month of Antibiotics , now wags her tail, and, with the exception of about 2 inches, all of her hair had grown back and her tail was fuzzy....and then she started chewing off her tail! I know the dog has some anxiety issues and we had a major change in our schedule last week. I can't help wonder if that's what started the chewing. She is going to the vet today. I am guessing her tail will have to be docked. I was wondering what you did with your dog to prevent more damage to the tail.