My poor hen sat on her nest for the full 21 days. Around day 17 I peaked under my hen and I found one of her eggs had broken. I promptly removed it and checked the other eggs. They were pretty gooey on the surface and the smell from the rotten one was pretty bad. I cleaned up the nest as well as i could put in fresh bedding and some fresh her herbs. Long story short, within the next three days all the eggs rotted one by one until we lost all seven. My question is what happened and how can I prevent this from happening again? I feel so badly for my poor hen. Her nest box was quite clean when she began sitting.