We have three standard donkeys. They are hit and miss with coyotes. They certainly bray when they see or hear them, but they have also been seen grazing while a coyote was walking near them in the day. You will never train them to leave dogs alone, they will stomp them every chance they get...
As I said I have tried, but some of mine haven't even started molting yet. As far as coyotes marking with scat, my dogs will do this as well when we take a walk back in our pasture, we recently put up some game cameras to see what's out there that's suddenly interesting to the dogs, we haven't...
A friend of mine had them kill one of her goats in the middle of the day, they will lure dogs out to them and kill them, I do have donkeys, but sometimes they don't do their jobs properly. Wolves used to keep coyotes in check, but people kill them more even though coyotes are more trouble.
I have three donkeys, sometimes they go after the coyotes sometimes they don't, they do stomp at dogs, goats, and an occasional duck, they also bray when the coyotes howl.
It took my husband weeks to actually see them, we ended up buying a cheaper night scope, the coyotes knew when he left for work and when I went out to feed them and would only come during that time, they came one night though and our donkeys started braying so he snuck out there's and put some...
Don't be so hard on yourself, I have a neighbor who keeps his in tractors, the coyotes have ripped open his pens and ate most of his meat birds. You'll have to keep them locked up now because they will keep coming back unfortunately. They got a bunch of my favorite birds a few years ago, my...