If you mean the American breed of cart horse, they are usually chestnut.
The American style Belgian comes in mostly Sorrel (Flaxen chestnut). While the true Belgian variety called a Brabant comes in many colors.
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.
Independently
Disease.
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
black white brown
all colors of horses
brown and cream colored
It's hard to say -- but people say horses can only see the colors purple, green, blue, and orange.
All horse colors can become grey.
No.