[pyrnet] Food issues

I'm having food issues again. I e-mail about two weeks ago about my Pyr pup. He's keeping my busy so I haven't had time to keep up with what's going on with the net. However, I need some more advice. First, he doesn't like to eat his food. I just think he doesn't like the way it tastes. He's on Nutro Large breed puppy. My vet gave me a bag of Eukanuba large breed puppy and I mixed it into his food. He eats the Eukanuba better, but his stools are still not normal. Anyone have any advice. He also has a rash under his fur on his shoulder. The vet has given me steriod drops for his eyes and Benedryl for his itchy skin. I do bath him in a medicated shampoo every week. I'm wondering if maybe what he is eating is contributing to the problem. His old owners had him on Pro-Plan and I got them to swith him to Nutro. So he's been on Nutro since July. Anyone have any suggestions.