When do I stop turning chicken eggs?

After day 18, according to Mississippi State's incubation table. From then on leave the eggs still, raise the humidity, and keep the incubator closed so the chicks can get into position.

What temperature and humidity do chicken eggs need?

Mississippi State lists 100°F in a forced-air incubator (2 to 3 degrees more in a still-air one). Humidity is a wet-bulb reading of 85 to 87°F until day 18, which works out to about 54 to 59 percent relative humidity, then 90°F wet bulb (about 68 percent) for the hatch.

When should I candle chicken eggs?

Mississippi State suggests a first test after 4 to 7 days, when a live embryo looks like a spider with veins for legs, and a second after 14 to 16 days. This calendar marks days 7 and 14. Candle in a dark room and handle the eggs gently.

Why didn't my eggs hatch on day 21?

Temperature is the usual suspect. Mississippi State notes that an incubator running consistently cool produces a late hatch and one running warm produces an early one, and that a thermometer off by a single degree for the full 21 days can seriously interfere with the embryos. Check your thermometer against a second one before the next batch.

Free tool

Chicken egg incubation calculator

Chicken eggs hatch in 21 days. Enter the day you set them and get the whole hatch on a timeline, with the incubator settings and the source behind every number.

Date eggs were set

The classic 21-day hatch, and the one number every source agrees on. Stop turning after day 18, raise the humidity, and keep the lid shut until the chicks are dry.

0
Set eggsTue, October 6, 2026
Eggs go in the incubator. Begin turning (or confirm the auto-turner is on).
7
First candlingTue, October 13, 2026
Look for spider-web veining. Remove clears and early quitters.
14
Second candlingTue, October 20, 2026
Embryos should fill most of the egg with a clear air cell. Remove any quitters.
18
LockdownSat, October 24, 2026
Stop turning, raise humidity, and keep the incubator closed until hatch.
21
Hatch dayTue, October 27, 2026
Pips and zips! Leave the chicks in until fluffy and dry, up to 24 hours.

Downloads a .ics file that works with Apple, Google, and Outlook calendars.

How long do chicken eggs take to hatch?

21 days, and for once the references agree. Here is what each one prints.

Source	Days to hatch	Applies to
Mississippi State University Extension	21	Chicken
University of Kentucky Cooperative Extension	21	Chicken
Minnesota Extension Service, University of Minnesota	21	Chicken

Incubator settings for chicken eggs

Temperature: 100°F forced-air (add 2–3°F in a still-air incubator)
Humidity to day 18: about 54–59% (wet bulb 85–87°F)
Humidity for the hatch: about 68% (wet bulb 90°F)
Stop turning: after day 18
Open the vents further: day 18

These come from Mississippi State's incubation table, which gives humidity as a wet-bulb temperature. We converted it to relative humidity with the same extension chart, so treat the percentages as close, not exact. Follow your incubator's manual where it differs.

Inside the egg, day by day

Twenty-one days from a single cell cluster to a chick that walks. This is what the embryology tables say is happening while you wait.

1
The outline of a chick
Within the first 24 hours the embryo lays down the start of its gut, backbone, nervous system, head and eyes.
2
The heart starts beating
The heart forms and begins to beat at about 42 hours, the first blood vessels form, and the ears begin.
3
Wing and leg buds
The nose, legs and wings begin to form, in that order, between hours 60 and 64.
4
A tongue, and darker eyes
The tongue begins to form and the eyes start to take on pigment.
5
Hen or rooster takes shape
The reproductive organs form and the sexes differentiate.
6
The beak begins
The first sign of a beak appears.
7
An egg tooth and toes-to-be
The egg tooth is distinct, digits appear on the wings and feet, and the heart is now fully enclosed in the chest. A common day for the first candling.
8
First feathers
Feathers begin to form along the back.
9
Toes
The toes are formed.
10
The beak hardens
The beak begins to harden.
12
Down
Down covers the body, the eyes are nearly closed, and scales show on the shanks.
13
Scales and claws
Scales and claws appear.
14
Turning toward the exit
The embryo turns its head toward the air cell, getting into position to break the shell. A good day for the second candling.
16
Everything firms up
Scales, claws and beak become firm and horny.
17
Beak to the air cell
The beak turns toward the air cell and the head tucks under the right wing.
19
Packing lunch
The yolk sac begins to draw into the body.
20
The first breath
The yolk sac is fully drawn in and the chick fills the whole egg except the air cell. Its beak pierces the air cell and it starts breathing with its lungs.
21
Hatch day
The chick cuts around the shell with its egg tooth, resting between efforts, then kicks free. Leave it in the incubator until it is dry and fluffy.

Hatching something else?

Common questions

How long do chicken eggs take to hatch?: Chicken eggs hatch in 21 days. Every reference we checked (Mississippi State, Univ. of Kentucky and Univ. of Minnesota) gives the same number. A day early or late is still normal: warm incubators run fast and cool ones run slow.
When do I stop turning chicken eggs?: After day 18, according to Mississippi State's incubation table. From then on leave the eggs still, raise the humidity, and keep the incubator closed so the chicks can get into position.
What temperature and humidity do chicken eggs need?: Mississippi State lists 100°F in a forced-air incubator (2 to 3 degrees more in a still-air one). Humidity is a wet-bulb reading of 85 to 87°F until day 18, which works out to about 54 to 59 percent relative humidity, then 90°F wet bulb (about 68 percent) for the hatch.
When should I candle chicken eggs?: Mississippi State suggests a first test after 4 to 7 days, when a live embryo looks like a spider with veins for legs, and a second after 14 to 16 days. This calendar marks days 7 and 14. Candle in a dark room and handle the eggs gently.
Why didn't my eggs hatch on day 21?: Temperature is the usual suspect. Mississippi State notes that an incubator running consistently cool produces a late hatch and one running warm produces an early one, and that a thermometer off by a single degree for the full 21 days can seriously interfere with the embryos. Check your thermometer against a second one before the next batch.

Where these numbers come from

Important Incubation Factors. Mississippi State University Extension.
Development of the Chick (ASC-195). Tony Pescatore and Jacquie Jacob, University of Kentucky Cooperative Extension. December 2012.
Hatching and Brooding Small Numbers of Chicks (AG-FO-0631). Melvin L. Hamre, Minnesota Extension Service, University of Minnesota. Reviewed 1990.
Care and Incubation of Hatching Eggs. Dr. Tom W. Smith, Mississippi State University, Poultry Science.
Testing Incubated Eggs for Embryo Development. Mississippi State University Extension.
Stages in Chick Embryo Development. Mississippi State University Extension.
Small Flock Series: Incubation of Poultry (G8353). Jesse J. Lyons, University of Missouri Extension. Revised September 2017.
Reasons for Poor Hatches. University of Illinois Extension.

We read each document ourselves and last checked this page against them on October 5, 2026. Where they disagree, we show you the disagreement instead of picking a winner quietly.

Get a nudge on lockdown day

Log the hatch in PoultryPal and it counts down with you, then records how many chicks hatched and your hatch rate. Premium adds lockdown and hatch-day reminders. Free to download on iOS and Android.