My hen is brooding out 4 eggs that were due 3 days ago. Still no chicks though. Now, 1 of the 4 eggs has dissapeared! It was there yesterday and now its gone without a trace. I looked all around and couldn't find it. I lock the henhouse at night so nothing could have gotten in at night. In the morning I open the door up to her individual cubicle for fresh air. Now, an egg is gone?? What happend????!!!!!!!!!!!