[ktj001]

I have an 18 month old Greyhound cross (90% Greyhound and 10% Scottish Deer Hound) and am having a lot of trouble finding a food that agrees with her. The only information I can find is directed at ex-racing dogs.
I was wondering if anyone out there has any advice on what to feed her, I have tried Go!, Now! and are now on A Taste of the Wild, lamb variety but she suffers from boughts of loose mucasy stool, vomitting, and not eating anything but grass. There is nothing physically wrong with her, she's been checked out at the vet so I'm assuming it must be the food.
Any advice would be greatly appreciated.