It depends on the mother and father.
For example:
The Sire was chestnut and the Dam was Bay. The choices are going to be only Bay or Chestnut from her sire and dam. If he/she has the dark points it's a Bay.
you can tell by it's ability, height, colour of it's coat and even weight.
Black colour
The horse was a bay
the haflinger horse can be chestnut or palomino
A horse that is white any other colour exept black is called skewbald :)
The colour of a foal dpends on the colour genotypes of the parents. A horse has dominant and recessive colour genes. The mix of these in the parents is what determines the colour of the foal. The coat is not always an indication of the colour genes that a horse has. In some breeds, certain colour genes have become established and dominant, such as in the chestnut Suffolk Punch draft horse.
A skewbald horse is one that has patches of colour, but this colour cannot be black.
You can't give it a other colour. You must agree the colour of the horse that you buyd
pink =D
white
Brown
bay