I bought Diesel the Natural Balance Duck and Potato dry food. He loves it. The pieces are a little bigger than his old food (Eukanuba) but he can't wait to eat at meal time. I add a little water to his food to soften it up because he is losing his baby teeth but I have no problem making him eat. I also buy the beef rolls but mainly use them as a treat instead of a meal. Maybe you should try dry food.
Reagan