Was he stable on the non-chicken/grain diet and then had a flair up or has he continued to itch even though you have limited his diet? That difference could be important in helping you figure out what is going on.
For instance, if he was stable on his diet, perhaps you should double check all the food packaging to make sure a recipe hasn't changed or if you have tried a new treat or chew, double check to make sure those are grain & chicken free. I had this happen with some of the wet food we were using, the oil it in came from a different source than the same brand dry food. Also I have to be really vigilant that no one gives Ollie treats I don't know about (in-laws, neighbor kids) or that he finds crumbs on the floor.
On the other hand, if he his itching only reduced but never went away on the limited diet, you might still have another food ingredient that is giving him trouble. Perhaps you should try just limiting him to a single protein (pick maybe only lamb or only venison) and see if that helps.
Finally, many places have a hospital or other health department that tracks pollen counts for the area. It could be that he has a pollen allergy too and cottonwood or ragweed is super high in your area and giving him trouble and he may go back to being ok when that pollen drops. Your Vet may suggest short term benadryl or Zyrtec if that is the case.
Just a few things to check that might give you an easy answer.
Traveler's Mom is right about apoquel. We use if for Ollie, it does work wonders to calm itching, but doesn't get to the root of the problem and is still in very limited distribution through certain Vets.
Jack- GSD/Husky Gotcha 7/24/2005- Rainbow Bridge 4/7/2012
Ollie-GSD DOB 4/15/2013
Last edited by Oliver'smom; 08-18-2014 at 02:08 PM.