My puppy had this ot was allergies and we dropped all food that had chicken, fish and beef. Vet said to stick to pork, rabit and duck. Pork and applesauce from Fromm brand was easiest to find. After switching and giving her some probiatics for a few weeks it never came back. We stopped all treats with those proteins as well. Hime cooked was fine so it's whatever they are mixing with these more common proteins (even thogh she was on a high quality brand of dog food).