Most white Icelandics once they go through their first molt will show some color, even if its just a single dark feather.
White would have been a predator target, so the genes would be scarcer in the general population.
My theory anyhow. White doesnt have a real high survival value in a ranging homestead breed of chicken.
I agree with that. I had 8 white(ish) chicks from eggs I got from NotAFarm and kept the pullets but not the cockerels. It's really difficult to predict what you will get when you cross a certain pair. That's the fun part about Icelandics