My boys are on IAMS... the GSD is not interested in food and when he has his dinner he walks off and looks at birds, IAMS is the first food that he wiggles his tail for.
My Rotty eats anyhting but I have noticed on IAMS the dog bombs are smaller and smell better. I had to use Optimum for a week and boy, the yard smelt so bad I had to keep windows closed.
Big dinosaur bones weekly and some scraps.