Japanese Yellow hens are typically infertile ???

[XP_2600]

I just read this:

The Japanese Yellow is a truly beautiful mutation. Birds of this color are a slightly clearer yellow than with the American Yellow mutation, but the blue of the rump is more intense.
Unfortunately, Japanese Yellow hens are typically infertile. Since the mutation inherits recessively, the best strategy with these birds has been to breed a visual male with a split yellow female.

at http://www.africanlovebirdsociety.co...ics/yellow.htm

anyone can confirm it?, i think i saw some Yellow Japanese laying eggs normally!