Why would a dog chew its own rear end hair out?
There are a couple of reasons. But this would best be answered by a liscened animal doctor.
But here's my best guesses:
1. Its got worms. Causing uncomfortable feeling and itching.
2. It is stressed.
3. Maybe pregnant if female.
Make it unpleasant for the dog - either by spraying a foul-tasting gear over your stuff, or by squirting the dog with a water pistol when you see him starting to chew something. It he is a young dog, he is still developing his teeth and needs to chew, so buy him something he can chew on, like a chew-toy, and encourage him to use that instead of your household possessions. A short-term solution is…
fleas. fleas fleas fleas. your dog has probably determined that the claws on its rear legs aren't sharp enough, and has thus resolved to use its teeth to scratch the bites. I recently had an allergey testing, and i found it difficult (before cream was applied) to resist the urge to chew my own back, because it itched so much.