I've posted recently about a broody hen on eggs, we had one egg hatch yesterday. When I candled them last around what I thought was 17 days, the 6 eggs we had, the chick was pretty much filling up the egg with normal size air sacs in all. When I checked on the new chick a bit ago and the remaining eggs, I decided to just put a light up to the end of them to see if there was any internal pipping and one of the eggs has a HUGE air sac now? It wasn't like that a few days ago, it's taking up almost half the egg now? What happened? There is also one other that has a large air sac, not as large as the other but it's still much larger than what I think it should be. Can anyone tell me what happened, can I assume the chick in the one egg is dead if the air sac has suddenly taken up half the egg?