Blue Swedish ducks are a medium sized duck, weighing between 6.5-8 pounds, with males being larger than females. They are a hardy breed, similar to a Rouen. Blue Swedish ducks have a lovely blue-gray feather color and white chests. Blue Swedish ducks are difficult to breed, as the blue color is a recessive trait, only obtained by breeding parents who are heterozygotes for feather color. This means that if you breed two blue swedish ducks, only 50% of the offspring will be blue swedes. 25% will be Black Swedish ducks and the other 25% will be Silver or Splashed White Swedish ducks. Another key feature of a Blue Swedish duck that is of perfect breed standard is that the first three primary flight feathers will be pure white.