As haleycookie mentioned, the only accurate way to determine food allergies/sensitivities is through an elimination diet and Hill’s ZD is the perfect food to start that with. If your vet did not discuss with you, then for 12 weeks only feed the Hill’s ZD with absolutely no other food. If you need to give treats then use the kibble, or buy the ZD treats. After 12 weeks and no issues, then slowly introduce a new food to see is there is a reaction. This is how a proper elimination diet is done so please discuss this with your vet. If you can find foods where there is not a reaction, then you will have other choices, but do the full 12 weeks before considering adding another food.
