I started by new 7 week old on Purina Puppy Chow because that is what the breeder was feeding her. I was at Petsmart yesterday and I had all these sales people promoting their food like Nutro Max and Blue and these natural and organic foods. They said my food has by-products including feces in it and theres are much healthier. Are these other brands really that much better? I just want to feed the healthiest thing that still tastes good. Thanks.