Last two hatches I’ve only gotten around 50% of my eggs to hatch, even though they were candling fertile early on. What are the most common reasons hatch rate drops off between candling and lockdown?
Hey Ron, that’s a frustrating spot to be in, especially when you know the eggs started out fertile! Dropping off between early candling and lockdown usually points to a handful of usual suspects:
Humidity swings — This is the #1 culprit. Too low humidity during incubation days and the air cell gets too big too fast, membranes shrink-wrap the chick; too high and chicks can drown in fluid or just be too weak to pip. For Coturnix, aim for roughly 40-50% humidity days 1-14, then bump to 65%+ at lockdown (day 14-15 typically, with hatch around day 17-18).
Temperature stability — Even small swings (a degree or two off 99.5°F for forced air) over many days add up. Check if your thermometer/hygrometer is calibrated and placed at egg level, not up near the lid.
Turning issues — Not turning enough (or stopping too early) before lockdown can cause the embryo to stick to the shell membrane.
Ventilation — Not enough airflow can cause die-offs mid-incubation even with temp/humidity dialed in.
Storage/handling of eggs before incubating — If eggs sat around too long or got jostled hard before you set them, that can cause early development to stall silently even after fertile candling.
A few things that’d help me narrow it down: what incubator are you using, and are you seeing the die-offs happen at a specific day range when you candle again? Early death (days 3-7) points more toward temp spikes or genetics; later death (days 10-14) leans more toward humidity or ventilation.
If you’re not already tracking your incubation days and candling notes somewhere, the Quail Keeper Max app has a hatch tracker that can help you spot patterns across batches — worth a look if you’re doing this regularly.