It's a tough question I've been dealing with the same problem. I started feeding my 3 dogs home coocked and I saw great benefits in it even though other people say its bad ice truly seen dogs live longer on a home coocked based meal diet. But if not possible you can also try Orijen. Orijen is said to be the best dry food out there and you can't get better than that. Although its hard to find and most of the time you have to order it online but its the best. I've gone to pet stores to shop for toys and clothing for my dogs and sometimes the food representatives that stand in the store asking what do you feed your dog and trying to promote their brand they will ask me what do I feed my dogs? And I tell them I feed then orijen and they say oh ok you got the best you can't get better than that. So I guess it's a really good brand the I ingredients are great.
So maybe you can try that.
Good luck and hope to hear how it goes