Easiest way to pick out a quality dog food is check out the dog food isle at Walmart. Those are all garbage. It's like putting your dog on a diet of hot dogs and french fries and wondering why they have issues.
Go to an actual pet store, and pick your favorite out of the top quality brands there. My dog does great on Blue Buffalo - Lamb or
Avoderm - Lamb. The Avoderm actually smells like avocados, when my dog get's a whiff of that, the drool is flowing.