I feed Natures Domain Salmon and switch it up occasionally with the Kirkland lamb. This has worked well for us for about three years. I recently bought a new bag of the ND salmon and although Elliott seems fine with it, Lea, has been having some stomach gurgles and seems more gassy, and her poos have been less firm. I usually add human glucosamine & chondroitin and a fish oil pill, but a couple of weeks ago I also started them on The Missing Link joint and coat supplement, and Naturvet digestive enzymes and probiotics (they turned 9 & 10 last month and I felt like I should be adding something more to ensure continued good health) so it is hard to know whether it is the food or the extra additions. In reading your posts about ND, I am wondering too if maybe ND changed their formula, or maybe we got bags from the same batch (I got mine at the Clackamas Costco store). For now I've taken Lea off the probiotics and missing link for now to see if her tummy is happier. If it doesn't resolve in a few days, I'm going to get a bag of Kirkland lamb, since that is what I usually rotate with.