I had a pure Colby bitch 10 years ago who's tail would bust in the crate, on walls, and on the chain. I was able to heal it up by applying super glue to the tip. It formed a hard seal and allowed healing from the wound bed out until it closed. Long term I also added fish oil supplements and to the high protein kibble I was feeding. I would also add eggs to the kibble. This seemed to work as her tail never broke open. The fish oil was recommended by Lou Colby. He mentioned her skin may be too dry.