We have decided to stop the raw food, JUST FOR NOW, as there are too many variables in it, until we figure out what he has a reaction to.
I have been trying to stay out of food/health discussions, because I think my stance is fairly clear, but I couldn't let this go, so I apologize in advance.
What variables?
Ingredients in raw chicken:
Chicken.
Ingredients in Hill's:
Potato, Potato Starch, Salmon, Potato Protein, Pork Fat (preserved with Mixed Tocopherols and Citric Acid), Soybean Oil (preserved with BHA, propyl gallate and citric acid), Natural Flavor, Dicalcium Phosphate, Fish Meal, Potassium Chloride, Powdered Cellulose, Fish Oil, Iodized Salt, Calcium Carbonate, Choline Chloride, vitamins (L-Ascorbyl-2-Polyphosphate (source of vitamin C), Vitamin E Supplement, Niacin, Thiamine Mononitrate, Vitamin A Supplement, Calcium Pantothenate, Biotin, Vitamin B12 Supplement, Pyridoxine Hydrochloride, Riboflavin, Folic Acid, Vitamin D3 Supplement), Vitamin E Supplement, DL-Methionine, Taurine, minerals (Ferrous Sulfate, Zinc Oxide, Copper Sulfate, Manganous Oxide, Calcium Iodate, Sodium Selenite), L-Tryptophan, preserved with Mixed Tocopherols and Citric Acid, Phosphoric Acid, Beta-Carotene, Rosemary Extract.
The Hill's has fish, pork, soy, sawdust, potato, and a bunch of sprayed on chemical "nutrients". How are you going to tell what he is allergic to? This doesn't seem to be simplifying the diet. And you know that cooked foods act on the body totally different than raw foods. So anything you decide he is allergic to in a processed food does not necessarily translate when you go back to raw, i.e. my Collie can't have beef based kibble, but can eat raw beef with no problem.
If you are feeding prey model raw (not prepared or dehydrated "raw"), then you should have no trouble controlling the ingredients list. Starting the Hill's is just a decent into a year of trial and error and loose stool and more allergic reactions, all for nothing when you go back to raw. So simplify the raw diet down to one protein source, and go from there. Get rid of any supplements, treats, etc. Keep it simple.