Different Breeds of Dogs Have Differing Nutrition Needs
There is no "best" food for all dogs, as each dog is an individual, and what works well for one dog may not work at all for another. In addition, it is better for a dog to get a variety of foods, rather than just one food for its whole life. Feeding different commercial diets can help fill in nutritional gaps that a particular food or brand might have, as well as making it less likely that your dog will develop food allergies. Rather than trying to find one "perfect" food, it would be better to find 3 or 4 different brands using different protein sources that your dog does well with, and rotate between them, anywhere from daily to every few months. In addition, I suggest adding some fresh foods to the diet, no matter what you feed, including eggs and meat (raw or cooked), canned fish with bones (Jack Mackerel, Pink Salmon, Sardines), dairy (yogurt, cottage cheese) and healthy leftovers (see Adding Fresh Foods below for more info). When you feed the same food continuously for a month or more, be sure to make the switch gradually to avoid digestive upset, but dogs that are used to getting different foods all the time rarely have any problems with it.