Kidneys and liver work overtime. Dogs may chew their lower backs. Feet may swell, so the dogs lick their feet. Natura alleges that although sorghum is good source of carbohydrates, it is low in digestibility. Because of this, pet food companies can use the cheaper by-products of human food production, such as Soybean Meal.
Meat is always the best source of quality protein.
Meat protein is better absorbed and retained and is higher in essential amino acids like methionine, arginine, and taurine. I could recommend any of the kibbles that use only human grade products. You would need to investigate further to determine accesibility, cost and ascertain that your dog had no allergic reactions to any of the ingredients. I believe that no matter which kibble you choose, you will need a supplement. No kibble, since it is processed at over 120 degrees, can contain all the vitamins,minerals, enzymes that are needed for a well-nourished dog.