I've been watching these two on the farm across
from the business I work at.
They seem to favor this particular spot of shade.
Most donkeys, regardless of coat color, will have dorsal stripes and shoulder crosses, dark ear marks, as well as the "light points" - white muzzle and eye rings, and white belly and inner leg.
Leg barring ("garters" or "zebra stripes") may be present as well.
Small dark spots right at the throatlatch, called "collar buttons" are a good identifying marking and occur occasionally.
I love learning; don't you?