I have always used Purina One it was what my first dog ate and liked so that's what I ahve stuck with, sometimes I have to use Purina Pro Plan becuase they are out of the Purina One. I tried switching it to a natural dog food I think it was Ultra, but even after a week of weaning them on to it, my older dog had the runs so bad, and I was tired of cleaning the kennel out, so she went back on Purina One and it cleared up that day, I think she is just be one it so long that trying to change it was a mistake. #2 also likes Purina and #3 is on the large breed puppy Purina one.