Hi Trish, sorry to hear that the chewing is not getting better. Are you sure that its food allergies and not environment allergies? I thought for a while when Nelson was getting hot spots and scratching that it was food related but the vet seems to think otherwise, he says its more likely to be environment. For e.g Nelson had rash and red lumps on inside of leg which I thought was reaction to one of the proteins but the vet said they were ant bites! Nelson developed hives all over his body recently and the vet thinks its a reaction to the bites!!
My vet was keen for me to get the allergy testing done but I have said no, even if it comes back that he is allergic to grass and sand for example I'm not going to stop him going outside and having fun being a dog! If all else fails, allergies can be managed with very low doses of steroids to improve quality of life. My vet said they are fine in very low doses even over long periods of time.
It really is a guessing game, don't give up on the raw and remember Karen said that it can take months before you see the full effect (the body has to build up the immune system).