It's like a play, and the director cues the snow, and instead of letting the flakes drift down on the actors they just dump the whole dang box of snow all at once.
I put a dozen in my incubator 2 days ago so hatch day would be the day my wife's friend visits. Should be a neat surprise. It's just my barnyard mix rooster with buff orpingtons, blue saphire, and a bcmxpolish.