No superstition involved at all, folks. They are just as described.
I don't have any. But I know of some folks that have some high percentage birds. They are basically a compilation of all the darkening genes available, (E, extended black allele; willow shanks, gypsy faced, fibromelanotic) and maybe another kind of fibro-like gene. I imagine it would be fairly easy to make a bird that dark using black silkies, sumatras, and some basic knowledge of genetics. If anyone is interested in this project let me know and I may be able to get you started in the right direction. I think it would be cool to have a longtail peacombed version of this bird.