I had an IBD Greyound and now I have one that has allergies. I feed her Wellness Limited Lamb and Oatmeal and it seems to be working. She is definitely allergic to Beef, Chicken and Turkey.
Also, if you find a food that works, Chewy.com is the best place to buy it. Their service is great and their prices are too. I have been using them for months with no problem.