I think they're primarily raised in Britain, but they're thought to be related to Dorkings, which are raised here in the US. There actually used to be Cuckoo Dorkings (with coloring similar to the Dumpies), but they're very rare if not almost impossible to find.
I've wondered the same thing myself. Being of Scottish heritage, I'd be very interested in raising Greys or Dumpies. If anyone can steer me in the right direction, I'd appreciate it.
I agree, I would love to find someone who has Dumpies in America. We heard that chickens with short legs are less likely to scratch up a garden, plus the short legs are fun looking
I checked Sandhill Preservation without any luck. So far no one on this side of the pond raises Dumpies.
So with the lethal gene, that means that they can produce long legged chicks just like the japs, a long legged dumpy would look almost like a bad maran. If you some how bred japanese bantams up in size, they would be a short legged chicken, just a thoght.