Since you said you have one with meat allergies, try meats that are purely organic. Your dog may be allergic to the hormones and dyes that are pumped into processed meats. You may be able to find a local farmer that can provide you with fresh chicken. Unfortunately, the organic meats can be really expensive. You can also try wild game, as it will be free of those dyes and hormones. If it truly is a protein allergy, then try switching the protein until you find one the dog doesn't react to. I have noticed a difference in the health of my poodles. Poodles are prone to seizures and I have a poodle that was having them quite frequently. He would seize a couple of times a month. Since we changed his diet, he has only seized twice in the past three years.