When we picked up Dexter from the animal rescue shelter two years ago, we asked what they fed the dogs. They buy the Costco brand lamb and rice by the 40 pound bag and go through several bags a week. They told us that a 40 pound bag would be long stale by the time our 16 pound terrier got through it, so they recommended Purina One Smartblend instead. He grew tired of the lamb and rice, and that is when we switched to the turkey and venison and then beef and sweet potato instead. Our vet also agreed with either the Costco or Purina One brands.