Sables have been eliminated from the conformation show ring by the American Spaniel Club. Sable can be "solid" or parti. There are black sables, red sables, and chocolate sables. There are also Merles. Like sables, this color is not considered an "acceptable" color for Cocker Spaniels and these dogs cannot be shown.
Sable isn't a confo eligible colour in the states.. but a merle is not eligible for anything period.
You can still show a sable in the CKC. People breeding merles are often skeazy losers that lie and register their dogs as roans so they can have 'papers'.
Reggin.. most people I see breeding merle cockers have really fugly dogs that barely look like the breed. Many have pretty byb lack of ethics. I've seen a scant few that look good.. but the ones that look like the standard often have very minimal merle on them.