Since spring, my poor GSD has been itching like mad. He eats grain free kibble with a mix of home cooked chicken, brown rice, and veggies supplemented with Vitamin E oil, olive oil, and flax seed meal for omega 3 and 6 fatty acids. He scratches his chin raw, he chews at his haunches and his tail, even though we bathe him every couple of weeks with skin soothing shampoo. I am sort of lost as to what else we can do to help him. Anyone have any ideas?