Try dropping the temperature to 98 to 98.5 on the last several days of incubation. I've done this and it consistently gets a better hatch rate from coturnix, ducks, and chickens. I think higher temperatures along with the stress of preparing to hatch can give hatchlings heart attacks in the shell. Remember, toward hatching time broody mommies stand up off the eggs more or spend more time off the nest . Mother knows best. Maybe it will work for you too.Ugh. I threw out 12 eggs. Out of those, 2 appeared to be fully developed but dead. They had feathers, beaks, toenails, everything. I have 7 left on lockdown but I just feel sick about it. Why do they die so close to hatching??