I think a six foot fence would stop any coyote from jumping. I really have never had any do any digging. My (?) coyotes have always just snatched them free ranging.
True story, once I was butchering two roosters. I caught the first one, culled him, left him on the table outside of the coop and went back to get the second one. Took me a bit more time to catch the second one. When I did, I noticed the first rooster was no longer on the table, but I thought he had just flopped off. Processed my second rooster, and then began to look.
That is a coyote. Quick and opportunist. I yelled out to the open prairie, "If you had waited 20 minutes, I would have plucked him for you!"
Mrs K