Fun!
With shovel, or digging equipment? On location, or did you have to load or drag the horse to the hole?
When I was 16, I was asked to help the dead-animal disposal guy haul off a dead horse at the stable where I was working. He had a dump truck with a large capstan rope winch mounted on the headboard of the dump bed. He just put a rope around the horse's head and reeled it up into the bed. Fast and easy. I was concerned he might rip off the head, but it didn't work out that way.