We are feeding our pup Diamond Naturals Large Breed Puppy. It's what the breeder fed. I have been told it's a good food, but am looking for something better. I see Acana recommended here again and again. So I looked them up and they have so many varieties! Where to start? Which line do you feed your rottie? Do you rotate the kinds, and if so, which ones? I'm in the states, in case that matters.