I have a 7 week old Nova Scotia Duck Toller. I have switched his food from "Purina puppy chow" to "Grain Free Holistic Select Adult & Puppy health". I was recommended this food by a few friends that have it for their adult dogs. Unfortunately the pet stores around here only carry the "Adult & Puppy" version and not the strictly Puppy one. Should I change to a Puppy food only? if so which brand? or will this "Adult & Puppy" be fine? Also, does 2 cups a day sound reasonable? I'm going by whats on the bag Thanks!