Originally Posted by smrobs
My first thought is that he may have a rabicano gene, that is the one that causes the skunk tail.
The grey hairs are probably the sabino gene.
Very true about the rabicano and sunk tail but the sabino gene WILL produce random grey hairs throughout the body. This is usually a minimal sabino and my own stallion has them.
His whole back legs are very pronouncedly grey but he is not grey himself but a dark bay. It happens to be carried in my boys sire line.