The Buff Orpington duck, sometimes called the Buff duck, is of English origin. The color should be buff or it is sometimes described as seal brown or rich fawn. These ducks should follow the Pekin in size and shape.
Reference:
All Breeds of Poultry, Origin: History: Description, Mating
and Characteristics, by Frank L. Platt. Published by AMERICAN POULTRY JOURNAL,
Chicago, Illinois.