There is really no "one best food". I would stick with what your breeder was feeding at first and then leave enough to mix slowly with whatever food you want to transition to.
If you're looking for foods available at Petsmart or Petco, Royal Canin, Wellness, Nature's Variety, and even Eukanuba has a few decent formulas.
If you're willing to go to a specialty-type store, I like Fromm, Annamaet, Dr. Tim's, Acana, Precise, and a few others. |