there is gelatin in gum...not made from hooves or chicken.
It is made from bones and cartlidge of beef and pork carcasses.
There are no actual bones but what happens is the bones, cartlidge, etc is boiled for a long time and then strained. That liquid, when cool, becomes stiff. Jello or gelatin.
Did you know that this liquid, minus the seasoning, is also called soup stock or broth...same exact thing happens when a turkey carcass is cooked after thanksgiving to make soup.
The major difference is commercial gelatin is also clarified and there is no seasoning so it has no flavor.