That's just so very sad about your donkey and the other losses.
It does seem very odd that the coyotes have started this only recently after years(?) of no issues. It crossed my mind wondering if part of the neighbor's flock was suddenly free ranged an/or in chicken wire only coops, and if they were the first hit, or if cats or dogs or other easy prey had ever came up slowly missing beforehand.
We did our best to try to fence out predators when living in the middle of coyote country, also usually had several large dogs, and used hot wire. Coyotes view dogs as either prey or competitors to be eliminated. That's why we usually had several med-large dogs (usually 4-5), otherwise they wouldn't stand a chance against the coyotes.
Unfortunately, not coyotes but neighboring dogs did much of our damages when we didn't have dogs, and were even caught several times in the act when we didn't have enough dogs for them to be able to fend off the pet dog packs that would be let run.
Coyotes and livestock attacking dogs were dispatched on our property.