Hi Sandy:
In the situation you describe I recommend that you consider trying"Solid Gold" brand dog food. It is a holistic type of dog food and comes in both dry and solid varieties. My Pyr has been on it for about four years, and does very well with it. I too had tried several of the major brands, all to no avail. My Vet. gave me a catalog of their products, and I have been using it ever since. It is available in Feed Stores. or you can access their website at www.solidgoldhealth.com, or call 619-258-1914, for a catalog. My Pyr gets a combination of the Hund-n-Flocken dry food mixed with a can of their Lamb, Brown Rice, Barley & Carrots with Sesame Oil.
Hope this helps;
Terry