Your diet looks good! My only suggestion would be to ditch the brown rice in favor of white because of the high arsenic levels and the phytic acid in brown rice. The latter is an anti-nutrient that will prevent them from absorbing minerals such as calcium & iron. I noticed in my own dogs an immediate increase in weight (they were too skinny) and improved activity when I nixed brown rice.
I also add sweet potatoes to their basic recipe for the Vitamin A, C, and potassium that can be harder to come by in homecooked diets.
