How was she around dogs? Burros in AZ attack dogs. Had one harass our dog all night while camping, had to put the poor thing in the truck, it was terrified.
I suspect the burros you encountered had been themselves harassed by dogs in the past.
Fucking colt snuck up on me from the back and bit me hard on the shoulder. When I jumped up to beat the shit out it the fucker did the old can't catch me nehhing business.
My quite short (~5') dressage champ younger sister had to punch way up when her horse was an asshole but I was very impressed to watch her discipline the horse.
I have hated horses all my life. My KLR650 is superior in every way.