You could be right about the protein level in the food, unless a dog is getting a lot of physical work a protein level of about 19 - 20% is plenty. Any higher and it has to find a way out somewhere, as it is not being utilised, and it usually comes out through the skin. When I worked with greyhounds they often had tails that bled and it was put down to wagging them against the kennel walls, but I am sure it was too high protein in their food when they were not racing and using it up. Try a chicken and rice type food and avoid too much red meat or high protein completes.