I'm a first timer and wasn't intending to incubate these ducks. Our mommy duck was killed while sitting on her eggs, so I am doing my best to take over. I have gotten some advice on how to know when to stop turning them and add humidity as I am not quite sure how to candle or know how far along they are. The eggs are really dark and full, with the top being clear (the air sac I'm guessing). Will that sac pop? Is that my sign that they will pip soon and I should then leave them alone? I'm so scared and confused - I need any advice you can give me. The internet has nothing to help!