When my puppy Koby first came to live with us he was eating Beneful and itching like crazy. We then switched him to Natural Balance's Sweet Potato and Fish, since that was what the pet store guy recommended for itchy pups. He has been itching less, but nonetheless, still itching. Could he be allergic to sweet potato? I've heard that some dogs are allergic to potato, but haven't heard anything about sweet potato. I want to switch him to something potato-less and something that has a meat, not fish, as the protein source. Also, is it better to give a food specifically geared towards puppies, or are all-life-stage foods okay?