I keep dark Cornish for both meat and eggs. They have a slight feral nature to them, meanign they wander much further than any of my other hens to find food. They also like to hide their eggs and fly much more than my other hens. Personally, I think they are awesome looking. Their eggs are medium sized, pale to medium brown. They contrast nicely with larger or darker eggs (I make my dozens look as varied as possible for customers). I had two go broody last year, which I believe may be a breed charateristic... although 2 outta 20 isn't overwhelming. One of my DC won run-upper grand chicken champion at the fair last year (one my Speckled Sussex got 1st).
What else. Oh, I have used my Dark Cornish Rooster to sire my own meat chickens. And he's in a breeding pen again doing the same. Typically, they are not raised as purebreds for meat (although there is a high end market for pure dark cornish chickens), but are crossed on other breeds with the Cornish being the terminal sire.
That's about it. Oh, in England they are called "Indian Game". So google that as well for more information.
