Im confused on why you keep calling him a dun, when the mare has dun qualities as well..?? There are many colts born this color and are still grulla but are mistaken for duns because of their first coat color, when they shed out to be their true mousey color. They both have the same marking and mind you he is only 6 weeks old and is still growing into his color, when he was just born his eyes and face werent near as dark and defined as they are now. His mother is a grulla and has the same dun marking as him, the ears, dorsal stripe into the tail, gaurd hairs, etc...so what would make the colt more "bay dun" qualities than his mothers grulla qualities... that's the part im not understanding?
You've got to give something you've never gave,
To get something you've never had. - Pat Parelli