A look at dun face masks around the world and on a variety of different breeds.
One of the characteristics of a dun animal is a variety of primitive markings, including a shading on the face that can resemble a mask. It is thought to be a form of camouflage, a throwback to wild equid animals. Generally the primitive markings are found in conjunction with each other and not all duns will display them. This marking specifically can be mistaken for the sooty modifier and the roan white pattern.
