I first noticed awhile back some white hairs intermingled in my horse's coat, on one spot on his shoulder. I guessed that it could have maybe been from the balnket he wore at the time rubbing, though it did fit.
I'm noticing more and more now though that he has some random white hairs... everywhere. All over his neck, back, shoulders and hindquarters. Very faint, hard to see. I'm attaching a very recent picture (not the best but I will take more) from a photo session I had with an amateur photographer friend of mine... so pardon the editing :P
He's only 13, by the way, so I don't think that it's age? And wouldn't that type of grey hair pattern appear more on his extremities?
Regardless, I hope someone has an idea!