My 8 1/2 month old Pitbull- Lab/ Mastiff Tessa has been chewing her fur for the past few months. She gets baths 3 times per week as my other two dogs do. She has raw spots on her fur where she chews and chews. My other two dogs do not do this. Recently she has begun chewing on my Pitbulls fur also. My other dog never does this but I catch Tessa chewing her Frequently, to the point that she has hair loss on her favorite spots to chew her, on her back. I dont know what to do to stop this.