Blue Swedish are similar in size to the Rouen and are very hardy ducks. They were developed in an area called Pomerania which comprises the coastal regions of Germany, Holland and Belgium. For many years this area was under the Swedish throne. As there are several written references to the breed in the 1850s, development probably occurred in the 1830s and 1840s.
The most interesting component of the Blue Swedish breed is the production of the blue color. Blue birds do not breed true. In other words, if you mate a Blue Swedish
with another Blue Swedish, only 50% will hatch blue. You will also get 25% black with white chests (called Black Swedish) and 25% that are a very light grey color,
often called Silver or Splashed White Swedish. To produce the blue color you must have heterozygote parents, meaning they have a black and a silver gene for feather
color. In addition, the first two or three primary flight feathers are pure white in a Blue or Black Swedish duck. This, along with the correctly sized white patch
on the chest, makes the Blue Swedish a difficult bird to perfect in terms of feather coloration.