Black Shoulders are a very interesting peafowl variety. The peacock looks almost exactly like an India Blue peacock except his wings have all black feathers lined with a blue-green shine. The peahen on the other hand, is white with grey-brown markings all over her, mainly on her back. The upper part of the back of her neck will have a patch of green feathers. Her flight feathers will be rust colored just like that of a peacock's. If you think peahens are a bit dull, black shoulder peahens are very nice looking.
Click on the following photos to see a larger version:
Peacock
Unfortunately I do not have a black shoulder peacock. I breed my black shoulder peahen to an India Blue peacock.
Peahen
A new surprize is that my black shoulder peahen pictured bellow, is actually split to white or pied. She has at least one small white flight feather that I noticed one day when she was sunning herself. Still, she does look almost just like a normal black shoulder so these are still relevent reference photos.