At least they admit you need supplements...
"Another supplement that we have included in our dogs* diets is nutritional yeast; either Red Star Vegetarian Support Formula or Lotus Brands * both of which are rich in B vitamins, and are fortified with Vitamin B12."
...Not sure on the definition of "vegan", but... um... they do realize Yeast is a living organism, right? not a plant.
B12 is required for both healthy dogs and humans, and is ONLY available via living organisms... meat, bacteria or yeast...
I get mine from meat.
(although I probably do consume plenty of bacteria and the occasional bit o' yeast)