I'm guessing those den sights, if active, are fox dens. Most coyotes don't use dens year around like a fox will. Coyotes usually will only use a den in severe winter conditons, and even then for a short period, and also during whelping season. Another time that a coyote may use a den would be if it was sick, such as having mange!
If you can hunt over the bait, and don't mind sitting out all night waiting, might take all night, might only take the sun going down to have action show up, then by all means, sit around and wait them out.
Or ya can shell out a few bucks and get a distress call, or two, or three, and learn how to call the furry critters to ya. Less time sitting around waiting this way, and lots more fun! Might be a little tough to call them to ya though, if they are getting a free meal every night, they won't be nearly as hungry and hence, not nearly as interested in a screemin' rabbit!