To be accurate, all three of these mutations are leucistics. In fact pied is a form of leucism. An animal does not have to be pure white with no colors or pattern for that to be the mutation at play.

Leucism is a defect in the pigment cells, this can be a complete or partial defect and the results vary according to how much or which pigment cells are defective.

Market names such as ivory, ultra and abu may be seemingly erroneous- but in fact are a great way to differentiate each mutation without qualifying one mutation as being leucistic and the others as being something else- since they are all in fact leucistic.

Regards,
Jordan