I would say they are at least day 7-10. You said it was about 1/4 shadowed, right? You are braver than I am though. I don't even try to get the eggs out from under my broodies!! I just watch them like a hawk, until they come off the nest. Then, while they're busy watching babies, I steal the other eggs, bring them in the house, candle them, and if there are any that are good, in the bator they go!! I would not put my hand in that nest for nothing...without a really thick, elbow lengthed leather glove!!