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I rotate your two regular Wysong kibbles in conjunction with Spot's Chicken Stew from the "Whole Pet Diet" by Andi Brown, which is cooking whole chicken with a number of vegetables and then running it the meat and vegetables thru a food processor. It's also easy to freeze the portions and our dogs really enjoy it. We also feed snacks of fruits, cooked eggs, cottage cheese, and high quality biscuits. So they should be getting a good variety. Also, C-Biotic and powdered bone meal.
Early in their lives we fed raw meat and bones (the breeder strongly urged this) but our vet who is probably the No.1 internist in Oregon (and neighbor) listed off all the bad things dogs can get from raw meat and strongly recommended against it.
One thing I remember reading quite frequently (maybe a myth) is that dogs like consistency in their meal everyday. Also I know that changing ingredients can result in loose stools and wiping bottoms is not much fun!
Net bottom line is that we want to keep them healthy and happy for as long as possible and are willing to make the extra effort vs. pouring stuff from a bag. So if you have any additional input it would be appreciated.
As our "vet," Dr. Wysong argues: animals in the wild have survived (and thrived) for eons eating raw, whole prey. That is the difference between reality and theory. Also, the numerous health problems plaguing pets today were not prevalent until pet owners in the U.S. (many other countries still believe in natural feeding) started feeding processed foods to their pets exclusively (the last 60 years or so). The risk of food borne infection is small compared to the risk of degenerative diseases caused by feeding processed foods for a lifetime. Please follow this link for more incite: http://www.wysong.net/pet-health-and-nutrition/should-you-feed-raw-to-your-pet.php.
Second, animals in the wild also do not consistently eat the same meal over and over again. Variation in diet would result from seasonal availability. Some days they do not even eat as food was not available. Periodic fasting is normal for animals and humans. It is incorrect to feed the same meal to a pet day in a day out; not only is it unhealthy, but it is also boring for the pet and can create food intolerances and finicky eaters (please see the attached articles, "The Myth of the 100% complete diet" and "I'm Confused"). From what you have written, it sounds like you are already giving them a healthy variety of foods. I would strongly recommend Dr. Wysong's book, The Truth About Pet Foods and the 100 Pet Health Truths program.
Additionally, once a pet is adjusted to a Wysong diet, you can freely rotate among them, as all of the Wysong diets contain the necessary probiotics and enzymes. For the past 35 years, tens of thousands of pets (including my own) have been fed following the principles in the Optimal Health Program and have all exhibited great health, including healthy body condition, normal digestion, clean teeth, lustrous coats and vibrant energy.