My little dog eats canned food. I have 4 or 5 brands I rotate, opening a different brand as each can is finished, so every other day or so. This has made her very tolerant to quick changes in food without the resulting gas and diarrhea. I can even add sardines, egg, or other toppers here and there with no problems.
My big dog eats dry food with daily toppers that I try to switch up frequently (eggs, sardines, chicken hearts,sweet potatoes, purĂ©ed spinach or kale). I buy her kibble in 30 -40 lb bags because it’s cheaper that way, and change to a new brand of food as each bag is finished. When I’m down to the last 1/5 or so of the old bag I mix it 50-50 with the some of the new food. Seems to be working ok, no diarrhea or anything, however I still haven’t found a food that gives her real firm poops. She seems to do better with fish-based kibble, but the brand she did the best on , Holistic Blend Marine, jumped in price from $60 to $80 something, so I’m experimenting with other fish based kibbles but so far I haven’t had has as much success as I did with Holistic Blend.
