Joe for years in Israel they have been trying to breed birds like that. To my knowledge there has only been one bred before yours. The gene that caused this is supposed to be a fatal gene, kills the chick in the egg.
Palamino horses can carry a fatal white gene from what the old-timers tell me. The rumpless gene is also a fatal gene as is the frizzle gene, again according to old-timers.
Joe can you say gold mine?