All horse colors can become grey.
Horses are different colors because different kinds of horses are naturally different in color. Some horses were also bred to be certain colors.
Tennessee Walking Horses can be nearly every color horses naturally are.
They are only black. If they have any other colors on them they cannot be registered.
sea horses can change to all of the colors of the rainbow
through a process called breaking... I know it sounds terrible and they dont really "break them"
brown and cream colored
all colors of horses
black white brown
It's hard to say -- but people say horses can only see the colors purple, green, blue, and orange.
The process that led to greater diversity would be selective breeding carried out by humans. Humans saw a color they liked and began selecting for it in their own animals.
Black, Bay, & Brown
They have no preference to particular colors.