How the dates are counted
Day 0 is the day you set the eggs. Chicken eggs then hatch around day 21: most chicks pip and zip within a day either side, so the calculator shows the hatch day as the middle of a short window rather than an hour.
- Candling. 4-H embryology guides candle chicken eggs on days 7 and 14, and once more at lockdown (day 18). For other species we scale those days to the incubation length, so treat them as a guide.
- Stop turning (lockdown). The day after which MSU says not to turn the eggs. Raise the humidity and keep the lid shut from here.
- Open vents more. MSU’s day to give extra ventilation as chicks begin to breathe air.
Forced air or still air?
A forced-air incubator has a fan, so the temperature is close to even everywhere: MSU lists 100°F for chickens. A still-air incubator has layers of warm and cool air, so MSU says to run it 2–3°F warmer (about 102°F), measured at the height of the top of the eggs.
Incubation by species: forced-air settings, with the still-air offset
| Species | Days to hatch | Forced-air temp | Still-air temp | Wet-bulb, days 1 to lockdown → last 3 days | Relative humidity | Stop turning (day) |
|---|---|---|---|---|---|---|
| Chicken | 21 | 100°F (37.8°C) | 102–103°F | 85–87°F → 90°F | 45–50% → 65% or more | 18 |
| Duck (most breeds) | 28 | 100°F (37.8°C) | 102–103°F | 85–86°F → 90°F | 55–60% → 70% or more | 25 |
| Muscovy duck | 35–37 | 100°F (37.8°C) | 102–103°F | 85–86°F → 90°F | 58–60% → 65% or more | 31 |
| Coturnix quail | 17 | 100°F (37.8°C) | 102–103°F | 85–86°F → 90°F | 40–50% → 65% or more | 15 |
| Bobwhite quail | 23–24 | 100°F (37.8°C) | 102–103°F | 84–87°F → 90°F | 40–50% → 65% or more | 20 |
| Turkey | 28 | 99°F (37.2°C) | 101–102°F | 84–86°F → 90°F | 58–60% → 65% or more | 25 |
| Goose | 28–34 | 99°F (37.2°C) | 101–102°F | 86–88°F → 90°F | 58–60% → 65% or more | 25 |
| Guinea fowl | 28 | 100°F (37.8°C) | 102–103°F | 85–87°F → 90°F | 58–60% → 65% or more | 25 |
| Pheasant | 23–28 | 100°F (37.8°C) | 102–103°F | 86–88°F → 92°F | 58–60% → 65% or more | 21 |
| Peafowl | 28–30 | 99°F (37.2°C) | 101–102°F | 84–86°F → 90°F | 58–60% → 65% or more | 25 |
| Chukar partridge | 23–24 | 100°F (37.8°C) | 102–103°F | 81–83°F → 90°F | 58–60% → 65% or more | 20 |
Days, temperatures, wet-bulb and stop-turning days: Mississippi State University Extension, Important Incubation Factors. Still-air: add 2–3°F, measured at the top of the eggs (MSU). Relative humidity: Brinsea, Humidity during incubation for chickens, ducks and quail; other species show MSU's general 58–60%. Follow your incubator's manual first.
Wet-bulb or relative humidity?
Extension tables give humidity as a wet-bulb temperature; many incubators display relative humidity (%RH). The calculator shows both: the MSU wet-bulb target, and the %RH that Brinsea publishes for chickens, ducks and quail. For other species we show MSU’s general 58–60%, rising to 65% or more for hatching.