It's a "chicken" in a very loose term. Not a barnyard bird at all. More so a cage bird like a parrot or something. Very much a sensitive, hybrid derived breed. Can't take cold weather, can't eat corn (milo, millet, wheat, or barley), can't get it's tail pulled less it bleed to death. It's a very complicated fowl.
Stems from an ancient cross of a green jungle fowl male and a red jungle fowl female. Such an F1 cross is call a Bekisar. The Bekisar gave rise to several unusual breeds including, but not limited to, the Onagadori.
These are some pure Onagadori in Japan:
No pures are known to exist in the US, but we're getting close. :-)