Gunner has always had a nice coat, but the past two months or so, his skin has become really dry and flaky. The entire time I've owned him he's been fed TOTW pacific stream (fish). I don't bathe him unless it's absolutely necessary and he gets brushed at least every other day. Any ideas how to fix this? He's not itchy at all and doesn't lick his paws, so I don't think it's an allergy. Last time he was out of food, the store was sold out of TOTW so I got pro plan sensitive skin and stomach. I hated buying a purina product, but it was the best thing they had, and I know some dobes do well on it. He's almost through the whole huge bag, and if anything, his skin is worse. What can I do? Is there another kind of food I should try? Supplements? Help..the flakes are gross and his coat is dull.