I'm worried.. have 18 mallard duck eggs in my incubator. Three hatched yesterday, two are still in the incubator with pips and nothing from the others. I had to open the bator to remove the three that had hatched and refill water trays. I never heard any peeping (even from the three that are fine) before pips or hatching. I'm not sure what to do about the eggs left in the incubator. How long should it take them to hatch? (I candled them at 14 days and all were living and moving around in the eggs). Thanks!