Not typical for coyotes at all. Do you have groundhogs or gophers where you are?
I have seen coyote go into a hole in the middle of a field to take cover but rare. Coyote scatt is very narrow on each end and often has hair in it. Maybe they were digging out prey? Around here I would say an Armadillo but not sure if you have those there. Holes are a PITA for sure.
I agree that this is not coyote behavior at all, unless they are digging out voles or mice maybe? We have dozens of coyotes around us, and the only evidence is their poop occasionally and their vocalizing at night with some sightings as they cross our lower field to access the neighbor’s giant farm. Coyote dens are quite large and would be most likely in a sheltered area dug into a hillside, ravine, rock pile, etc. The farm up the road had one in a unused culvert for years and years. We’d trail ride and see pups pop out to take a look at us when we rode by.