You might want to look at the website for Precise Pet Foods and see if they have anything that meets your needs. http://precisepet.com/
Rocket has done well on both the Precise Foundation Chicken Meal and Rice, as well as their Senior Kibble. We ultimately got his tummy issues under control with Tylan, but he did best on these foods for longer time periods than on other foods. Now, with the addition of Tylan, the food is working great for him.
The various foods can be a little hard to find depending on your location, but we are able to order from WAG.com and Petflow. If we were in a larger city, we probably wouldn't have to order online, as it seems they have plenty of dealers in major cities. I am also able to have a local Feed and Tack store order it for me. .