Pheasants dying in eggs at various stages. What is wrong?

[chicken danz]

I had a group of 8 eggs in my incubator that didn't hatch. After extra time was up I checked the eggs to see if they had any development.
Two of the eggs weren't fertile, but the others had dead chicks at various stages of development, including one that looked full term down to one that was just a small dark shape. What could be wrong? Why would the pheasants die in the egg at different times. There have been no changes in the incubator. It is kept at 99.5 with air and turning and humidity. I move the eggs to a still incubator at day 20. These are Melanistic Mutants and their incubation period is 23-25 days. Any clues? thanks

 

[msheets]

Maybe it was just bad luck & all the deceased eggs were just naturally weak? My last hatch of chicken eggs were like that, they were dead at all different stages. My thermometer was wrong though, by -10 degrees! Do you know if your thermometer could be off? I think mine died at different stages depending on each chick's sensitivity to the temp, some handled the low temp longer than others...