Hmmm .... I wonder what dogs ate before "dog food" was invented? I don't own a dog (but love them and there are always several resident dogs where I live whom I adore) but the qualities of a premium dog food might include no gmo, organic (i.e. no pesticides), no man made chemicals, and should be edible by humans in a pinch 
They ate the owners when they got too old.
My 6 pound dog (overweight, Vet wants it at 5) never seen a cow, but loves beef and never seen a chicken, I wonder if the chicken or the dog will run away.
It chases squirrels, but the squirrel run as a courtesy, then laugh at the dog. She think she is as big as a Great Dane, will it try to chase a cow?
It would be funny to watch it trying to bite the cow ankles until it steps on my dog.