Amongst other dogs and hunting types I've messed around with,I had a Beagle trained to follow a blood trail. Hunters,landowners and an occasional game warden hired me and "Snoopy" Beagle to recover deer. In offseason training I realized Snoopy would latch onto most any scent I showed a bunch of interest in. Which bring's use to your suspicion of "fox family"being the culprit. By prearrangement,4 neighbors called me when momma fox were suspected of raiding chickens (always during daytime). Out those 4 times Snoopy trailed 3 fox to proximity of their dens,once pratically sticking his nose in the den. Coyote were probmatic but more fun. When coyote were seen attacking or stalking birds and sheep,about half the time Snoopy followed scent and "started" coyote. Larger,faster and more agressive dogs being held on standby would take over to chase. We got shots at a few,confirmed hit one but without fail the coyote was never seen again. A neighbor later hooked me on watching his walkers start coyotes,run them while he attempted intercepting chase and releasing sight hounds which quickly overtook and killed the coyote. I enjoyed the high speed truck chases almost as much as the dogs.