That's a good suggestion and thank you. Wish I had thought of something like that earlier. So far, he's been doing well by our mixing just a little of his old dog food, with more of the newer grain-free dog food. We're not done yet by any means with this experiment; and we're keeping an eye on him for the next few weeks to see what other options might also work out well for him Eventually, we're trying to find a more reasonably priced, long-term, dog food "combination" -- (feeding him a mixture of 1/2 of some regular dog food, and 1/2 of the premium, grain-free, salmon dog food from the pet store).