I rescued a nest of mallard eggs from being plowed under in a field. I don't know how far along they are. How do I know when to up humidity and stop turning? If I wait for a pip would that be too late? Or is there another sign I could look for to know if they will be hatching soon? I candled but I don't have enough experience to guesstimate how far along they are by the way the candleing looked. Any advice is appreciated. Thanks for taking the time to read this.