Probiotics and digestive enzymes will help with the gas, diarhhea, and ear infections. I would get him on them as quickly as possible. Human ones from the health food store will work. Find a probiotic with as many different strains as possible. You may find that some of his allergy issues are because his gut is not as resiliant as it should be and the probiotics help a lot. If shopping online Swanson’s has really good ones.
I would not feed a kibble with several different kinds of protein until you figure out which ones don’t bother your little guy. Stick with a food that has very few ingredients.
I also used Brothers Complete Allergy Formula and raw with good results, but my dog didn’t have the same issues or to the degree that your’s does, so while I believe it would help, I don’t know that it would solve all your dog’s problems.
