"I recommend choosing at least two or three different brands, using different protein sources, and rotating among them anywhere from daily to every few months. If one food is deficient in some areas, the odds are that the next food will make up for it, especially if it’s made by a different company -- though that food may be deficient in other areas.......Rather than relying on a single recipe created with a spreadsheet to ensure that your dog’s nutritional needs are being met, feed a wide variety of fresh foods in appropriate proportions; that's the best way to create a healthy diet for your dog, as well as for your family" from Variety Is Important for Nutritional Completeness by Mary Strauss in Whole Dog Journal "We know from studies using experimental animals that it is extremely difficult to induce nutrient deficiencies in animals that are fed a variety of foods providing sufficient calories. The best way to avoid nutrient deficiencies is to eat a variety of minimally processed foods. If you do that, you don’t have to worry about specific nutrients.” Marion Nestle author of Feed Your Pet Right: The Authoritative Guide to Feeding Your Dog and Cat
"Whatever diet you are feeding your dog, it is important to use several animal protein sources. This is what we call variety, and variety helps to make sure a dog is getting all the nutrients they need.....If you are feeding a raw diet, please use at least four protein sources, preferably six........For those feeding commercial pet foods, be sure to rotate brands of food to insure several protein types". from Protein and Variety in the Diet by Lew Olsen author of Raw and Natural Nutrition for Dogs: The Definitive Guide to Homemade Meals
