It is definitely easier to feed one type of food, but it can be a lot cheaper to feed two or more kinds. Especially if one dog has a special needs diet. That sucks that she's allergic to grain. I have heard great things about the Solid Gold, but have no personal experience with it. Aspen and Misty mentioned Pinnacle, that is what I feed Freckles and Dudley, but I dont' know if they make a formula with no grain.