Check with the breeder to see what they are feeding him, you don't want to make a change too quickly. We have been feeding Purina Pro Plan Large Breed Puppy and now transitioning to Large Breed Adult. This is what the breeder was feeding and I asked my vet and they said that of the foods that you can buy it's actually one of the better ones. Our boy has done so well on it, he has had no skin issues or allergies and seems to be thriving so we have kept him on it. There's lots of advice out there and lots to choose from, but it really boils down to what your dog does well on and likes to eat.