OK, eyes, feet, and gas all point to food. My dog went 6 months eating chicken (and other stuff) before I figured out it was the chicken causing the very mild reactions (weepy eyes, red ears, no hair). Change the food. The gas means her gut is having trouble digesting, which again points to the food. It might be a fine, quality food, but it's not right for her. The lack of variety in this case might be helping the problem along.
You don't need allergy testing. Get the food changed, let it settle for a few months. If she still has issues you can try Benadryl, which will help if it is seasonal/environmental allergies. My Collie used to get Benadryl, until I changed her to raw and her eyes cleared up.
She's had a chicken-based food since she was a baby, but my understanding is that, like a human, a dog can develop allergies at any time? Is this correct? Should I try a Salmon based food? Or a lamb based food? I saw that TOTW had a salmon and venison mixed. The vet said if we were going to switch foods to introduce two items she had never had before. She has never had salmon, venison or lamb.
Even though she had her anal glands taken care of yesterday she occassionally smells like that very distintive anal gland smell. GAG ME!
