Egg Incubation Calculator — Hatch Date for 10+ Poultry Species

Chicken eggs hatch in 21 days at 99.5 °F with 45–55 % humidity during incubation and 65–75 % during lockdown (last 3 days).

Standard duck eggs take 28 days. Muscovy duck eggs take 35 days — the longest of common poultry. Duck eggs need higher humidity (55–65 %) than chicken eggs.

Lockdown is the final 3 days when you stop turning the eggs and raise humidity. For chicken, that's day 18–21. High humidity keeps the internal membrane moist so chicks can pip and rotate without shrink-wrapping.

99.5 °F (37.5 °C) for forced-air incubators. Still-air incubators run at 101–102 °F measured at egg-top level. Even 1–2 degree deviations cause failed hatches.

Candling (shining a strong light through the shell) reveals whether eggs are fertile and developing. Day 7 shows veining in fertile eggs; day 14 shows the embryo; day 18 shows the air cell.

3–5 times per day until lockdown. Odd numbers of turns prevent the embryo from sitting on the same side overnight. Automatic turners rotate eggs hourly — ideal.

Fresh, fertile, well-stored eggs with proper incubation: 80–90 %. Shipped eggs: 40–60 % is typical due to handling damage. Heritage breeds hatch at lower rates than production breeds.

Avoid it. Opening the incubator drops humidity fast — the membranes can dry and shrink-wrap chicks. If you must, do it briefly and raise humidity after closing.