Just wondering what it might mean if the entire egg is dark. Is it rotten and ready to explode? Or is it getting ready to hatch??? Just wondering. I couldn't find an air cell anywhere and this is my first attempt at hatching... well, letting my broody hen hatch them. Any help would be great. THANKS!!! ETA: I also have another question: I know that on day 18 eggs in an incubator go into lock down, but what about when they are under a broody hen? Am I doing harm by continuing to candle them? I am not exactly positive on what day they are on, but I am sure they ought to be hatching some time this week. Again, Many thanks!!