Chicken Egg Incubation Calculator
Chicken eggs hatch after about 21 days, normally between 20 and 22 days from the start of incubation. A typical clutch is 8-12 eggs.
Chicken egg incubation calculator
Expected hatch date
Wednesday, 18 November 2026
Earliest
17 Nov 2026
Latest
19 Nov 2026
0 of 21 days elapsed
A chicken does not have a gestation period. Birds do not carry developing young inside the body: the female lays an egg and the embryo develops inside that egg, outside her, warmed either by a sitting parent or by an incubator. The correct term is incubation, and it is measured from the day the eggs are set or the parent begins sitting, not from mating and not from the day the first egg appears.
Key chicken incubation facts
- Chicken eggs hatch after about 21 days of incubation, with a normal range of 20 to 22 days.
- A typical clutch is 8-12 eggs.
- Incubation only starts when the eggs are sat on or set, which is often days after the first egg is laid.
- Poultry eggs are usually set in an incubator at 37.5°C and 55% humidity, with turning stopped a few days before hatch.
How to count the days
Day one is the day the eggs go into the incubator or the day a parent starts sitting continuously, not the day the first egg was laid. Eggs can be held for up to a week before setting without much loss of hatch rate, and holding them keeps the clutch hatching together. Stop turning around day 18 and raise humidity for the final days. If nothing has happened by day 24, candle the eggs before discarding them: a cool incubator can delay a hatch well past the average.
What temperature and humidity should a chicken egg incubator be?
A forced-air incubator (one with a fan) should run at 37.5°C (99.5°F). Still-air incubators have no fan, so the air layers by height; run them slightly warmer, around 38–39°C measured at the top of the eggs. Check the reading with a second thermometer, because built-in displays are often out by a degree, and a degree either way is enough to shift the hatch day.
Keep humidity around 45–55% for days 1 to 18, then raise it to about 65–70% for the final three days. Humidity controls how much water the egg loses; the air cell at the blunt end should grow steadily as incubation goes on.
How often should chicken eggs be turned?
Turn the eggs at least three times a day, and an odd number of times so they do not spend every night on the same side. Turning stops the embryo sticking to the shell membrane. Automatic turners handle this for you. Stop turning on day 18.
When should you candle chicken eggs?
- Day 7: a fertile egg shows a network of blood vessels spreading from a dark spot. A clear egg is infertile and can be removed.
- Day 14: the embryo fills much of the egg and the air cell is clearly defined.
- Day 18: a final check before lockdown. Remove eggs that show no development or a blood ring, which means the embryo died early.
What is lockdown and what is normal at hatch?
Lockdown is the last three days, from day 18 to hatch. Stop turning, raise humidity and keep the lid shut: opening it lets humidity escape and can dry the membrane around a chick mid-hatch.
The chick first breaks into the air cell (an internal pip), then makes a small hole in the shell (the external pip), and finally cuts round the shell and pushes out. Going from pip to hatch can take up to 24 hours, and pauses of several hours are normal. Chicks absorb the yolk just before hatching and can go 24 to 48 hours without food or water, so leave them in the incubator until they are dry and fluffy.
Common chicken egg hatching problems
- Early hatch (day 19–20): the incubator ran too warm.
- Late hatch (day 22 or later): the incubator ran too cool.
- Chicks stuck to the shell or wrapped in dry membrane: humidity was too low during lockdown or the lid was opened.
- Mushy, heavy chicks with unhealed navels: humidity was too high earlier in incubation, or the temperature was off.
- Splayed legs after hatch: a slippery surface; put chicks on paper towel or a textured floor, never bare newspaper.