I've seen white feet that are hard and strong. I've seen black feet that are weak, soft and shelly.
Research has been done on this (IIRC, by Doug Butler) and pigment, or the lack of it, is not the cause.
A white hoof tends to have thinner hoof walls. King Ranch use to remove them from their breeding stock.
To OP, most of that older stock was big headed and raw boned, not my first choice. To me, STOLI is about a perfect horse.
