Seems as though you are taking all of the necessary steps to get your bully in optimum health. We are currently doing the same, trying new foods and other things. Our best luck so far has been avoderm. One of our bullies does NOT take food change well. We have to switch her over a course of about 3 weeks, whereas the others can be done in less than a week. Go figure. Part of your issue could be switching too fast, like it is with our little Jesse. I hate to switch again, but I am still not happy with the current choice. Was very happy with the Avoderm, so now we are trying to choose between sticking with that, or trying Fromm. Should I go with what I know they did well on, or go with a food I have heard wonderful things about. It is a tough choice.