I feed a chicken base for the raw with a rotation of venison, beef, lamb, and fish mixed in. I've singled out that flaxseed oil, oatmeal, pork, and excess chicken skin cause itches. I was confused about the skin, but after taking the skin off, no more itches.
Since singling those out of his diet, the raw has been good. The stool just doesn't seem to be where it should (he's going two or three times a day), and itches still flare occasionally. I had a limited allergy panel done when he was a puppy and there was only a mild reaction to pork, which has been kept out of his diet. Other than that, zero reaction to any other meats.
The NV that I got was the Instinct chicken one, so I don't see how it could be the chicken...?