I am trying to hatch out mallard eggs. They are fertile and they make it to the hatch date but, usually die in the egg before hatching. When I crack open the egg I find a fully formed duckling that has not absorbed the yolk of the egg even 2 weeks after hatch date). I keep the incubator at about 99.7 degrees Fahrenheit and try to keep the humidity at 35-40% I have an automatic egg turner and when the eggs are near to hatch date I move them to a separate incubator with a temp of 98.6 and 80% humidity, with a mesh floor and no turner. Does anyone have an idea what may be going on? Some of the eggs are WAY past their hatch date and there have been a few that I could detect no movement when candling for a few days so I opened them assuming that the duckling was dead, only to find a live duckling attached to a greenish yolk that has a nasty odor....some are just really really behind. I have unwittingly killed 3 ducklings because of lack of movement and being so absolutely behind their hatch date. I don't know what I am doing wrong. I am expecting the eggs to hatch by 28-30 days (I know that mallards are a bit less (26-28 days)) but, I am giving them a little bit more time. Any advice would be greatly appreciated. We really really want these little guys to hatch. Thanks so much for helping me get these little guys out into the world alive!!!