Saw a YouTube video of several fairly large dogs in Mexico after they came home with owner ---each with a ear of corn between his paws eating the kernels .This was dried picked ear corn . A old friend of mine from Miles City ,Mt ran two bands of sheep .They had lots of border collies for the herders,he said the only thing they fed was ground corn with bacon grease on it.This would have been in the 1930s thru 60s I would guess the herders got a few jackrabbits and antelope for them too.His Mom always sent them out in June to kill some antelope which she canned in pint jars for the herders .He said June was the best for antelope meat (green grass then ). These bands made a big circle about a 100 miles in diameter .