Hi Jen,
Your vet has run full fecal testing, I presume? You said he was eating the Canidae for “months” before the diarrhea started. How many months would you say that was? What Canidae recipe was he eating when the diarrhea started? What food/s was he eating prior to the Canidae and did he ever have loose stool before that which started while on the Canidae? Did the vet confirm a diagnosis for which the Rx food was prescribed – if so what was that and what is the food that was prescribed? OK, last question, has your dog been gaining weight and growing / gaining weight “normally?”
My first thought was that he may have had an intolerance to something in the Canidae and then again to something in the Wellness. Could be the same problem ingredient, could be different ingredients. You could try plain, canned pumpkin during a very slow transition to the new food along with Perfect Form by The Honest Kitchen.
