I agree about the chicken. A lot of dogs develop allergies to poultry. There are foods out there that are very limited ingredient with novel proteins that might work. It takes a few weeks sometimes to see any difference so you can't give up without giving the proper chance for the allergens to be eliminated from the body.
I do hope you are able to find something that works, you must be at your wits end! These are what I feed my two girls
Dick Van Patten's Natural Balance Pet Foods, Inc. They love all the LID flavors. If you buy at a larger pet store, you can return opened dry food and remaining canned foods for a refund if your dogs won't eat it.