Egg Incubation & Hatch Date Calculator

Quick answer: chicken eggs hatch on day 21. Ducks take 28, Muscovy ducks 35 to 37, geese 28 to 34, turkeys and guineas 28, coturnix quail 17. Stop turning three days before hatch — for chickens that is day 18 — and candle chicken eggs at 4 to 7 days and again at 14 to 16. Set the date above and the planner gives you every one of those days as a date you can put in your calendar.

Where these numbers come from

All thirteen species come from one published table: Mississippi State Extension’s Hatchery Management Guide for Game Bird and Small Poultry Flock Owners, which gives the incubation period, the dry-bulb temperature, the wet-bulb reading, the day the vents open and the day turning stops for each kind of egg. The chicken-specific detail — candling days, storage, the hatch window — comes from Mississippi State’s Hatching Quality Chicks (P1182) and The Avian Embryo (P1150).

Nothing here is interpolated. If a species is in the table, you get its own numbers; if a figure is not published for it, this planner leaves it out rather than guessing from a neighbouring bird.

The humidity disagreement, in one university

This is the part worth reading before your first hatch. Two Mississippi State documents give opposite advice:

• P1182 and the extension page: run 58 to 60% relative humidity (85–87 °F wet bulb) for the first 18 days, then raise it to at least 65% (89–90 °F wet bulb) for the last three.
• The hatchery guide: run the wet bulb at 85 to 87 °F from the first day until hatching is complete — and it warns that pushing the wet bulb to 90–92 °F “may decrease hatch” if the vents are closed too far to get it there.

Both are from the same university, and both are printed here. They are not really contradicting each other so much as weighing two risks: too little moisture at hatch and a chick shrink-wrapped in its shell, or too much and a chick that drowns or suffocates in a poorly ventilated machine. The air cell is the referee — P1150 shows what it should look like at 7, 14 and 18 days, and if yours is smaller than that your humidity is too high.

Turning, and when to stop

How often to turn is the other place the sources part company: P1182 says at least 2 to 3 times a day, the extension page says 4 to 6. Everyone agrees on an odd number of turns so the same side is not uppermost all night, on marking an X on one side so you can see that each egg actually moved, and on stopping three days before the hatch — day 18 for a chicken, day 25 for a duck, day 31 for a Muscovy, day 15 for coturnix quail. After that the chick is positioning itself to pip and needs to be left alone.

Before the eggs go in

Hatchability falls off fast with storage: P1150 says eggs older than 7 to 10 days drop rapidly, and at three weeks hatchability is near zero. Keep them around 55 to 60 °F at 75% humidity, small end down, tilted 30 to 45 degrees, and turn them daily if they will wait more than three or four days. Never let them get below 40 °F.

Under a broody hen

Switch the planner to the hen and the temperature and humidity disappear, because she does both better than any machine. What is left is the calendar: when to candle, when to stop lifting her off, and when to expect chicks. It is the same 21 days.

When they are late

A day either side is normal, and cooler running makes a hatch late. P1182 draws the line plainly: all chicks should be out by the end of the 21st day, and chicks that hatch after the 22nd are not usually healthy and vigorous. Give a quiet egg an extra day, candle it if you want to know, and resist helping — a chick that cannot get out on its own usually cannot for a reason.

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