If a greyhound can race on it then there can't be much wrong with it.
I feed raw chicken and tripe and use good quality dried food as a mixer, the pups the healthiest shes ever been.
I also don't go with this long term health business with feed, if the dog looks, behaves, races and works right then the right stuff is going in.
I myself got a bit too anal with it a little while back, why make your life too difficult.
Shepp