Great Lakes gelatin states they use skins from grass fed cattle. Not hard to believe seeing they use cattle from a country with lots of grass.
"7. Are your pigs or cattle fed any hormones or other kinds of artificial fillers?
There is no way to be certain of all concepts of feeding of these animals, but what we can assure you is that of all tests that are known to us we find no disease, Antibiotics , hormones, pesticides, or herbicides in the skin or hides of animals used to produce gelatin. Therefore none of the above items are transmitted to our products."