From MLive.com in Michigan:
BRUCE CROSSING, MI – What keeps a hungry wolf at bay? Turns out, an angry braying donkey that’s bonded with the other farm animals and doesn’t want to see them dragged away and eaten will do the trick.
In Michigan’s Upper Peninsula, some livestock farmers have turned to donkeys for non-lethal means of protecting their herds. The practice has historical precedent in Michigan, but has also gained in popularity worldwide.