A dog is a carnivour. Therefor, I would go for a carb-free kibble (if that exists), or at least a kibble with the most meat-parts and the least carbs (grains, potatoes, corn, etc). But personally, I would switch to raw feed. But if this is not what you wish, search for a good quality kibble, not made by Palmolive or Mars, or manufactured in China (!) but made by a company that produces kibble in the US. Also, check the anti-oxidants that are used in the kibble. Most anti-oxidants used in dog food are forbidden in our own food (poisoneous for us, but you can feed it to your dog!), like BHA and BHT.