21 Days to Hatch: How to Incubate Chicken Eggs
TL;DR: Chicken eggs incubate for 21 days at about 99.5-101°F depending on incubator type, with humidity around 50-55% for days 1-18 and raised to 65-75% for the final 3-day lockdown. Turn eggs 3-5 times daily until lockdown, then stop turning and leave the incubator closed. Candling at day 7, 14, and 18 tells you which eggs are still developing.
How Long Does It Take to Hatch a Chicken Egg?
Chicken eggs take 21 days to hatch from the start of incubation, though in practice a batch’s hatch is spread across roughly day 19 to day 22 rather than landing on a single day. The 21-day figure is one of the most reliably documented numbers in poultry keeping and holds regardless of breed — gamefowl, layer, or native chicken eggs all run the same incubation length.
That 21-day window breaks into three phases that need different handling: the main development period (day 1-18), where eggs are turned and humidity stays moderate, and lockdown (day 19-21), where turning stops and humidity rises ahead of hatch. Getting each phase right matters more than any single day — a mistake on day 3 is usually recoverable, but skipping lockdown prep is not.
What Should You Do With Eggs Before Incubation Starts?
Store fertile eggs pointy end down at a cool room temperature, and start incubation within about 7-10 days of collection, since hatch rates decline the longer an egg sits before incubation begins. Let stored eggs come up to room temperature for a few hours before placing them in the incubator, rather than moving them straight from a cooler storage spot into a warm incubator.
This pre-incubation window is easy to overlook when the focus is on the 21-day cycle itself, but an egg that’s been stored too long or too warm before incubation starts is working against you before day 1 even begins. If you’re collecting eggs from your own flock over several days to build up a batch, keep track of collection dates so you’re not incubating a mix of fresh and aging eggs without realizing it.
What Temperature Does an Incubator Need?
Set a forced-air incubator (one with a circulating fan) to about 99.5°F (37.5°C), or a still-air incubator (no fan) to 100-101°F (37.8-38.3°C) — the higher still-air figure accounts for the natural temperature layering inside a incubator without air movement to even it out. Getting the incubator type right before setting the temperature matters, since applying the still-air number to a forced-air unit will run it too hot.
Temperature swings matter more than small offsets from the exact number. A stable incubator running slightly off the target beats one that swings up and down, because embryos are more tolerant of a small constant offset than of repeated temperature spikes and drops.
What Humidity Does Incubation Need?
Chicken eggs need roughly 50-55% relative humidity for days 1-18, then a jump to 65-75% for the 3-day lockdown period before hatch. The lockdown humidity increase helps keep the internal membrane the chick has to pip through soft and workable — a chick fighting a membrane that’s dried out from low humidity is one of the more common causes of a failed or difficult hatch.
| Phase | Days | Temperature | Humidity |
|---|---|---|---|
| Development | 1-18 | 99.5°F forced-air / 100-101°F still-air | ~50-55% |
| Lockdown | 19-21 | Same as above | ~65-75% |
Humidity is harder to get precisely right than temperature in a humid Philippine climate, since ambient conditions push in one direction already. Check your incubator’s actual reading rather than assuming ambient room humidity matches what the eggs need — the two are not the same thing.
Why Do Eggs Need to Be Turned?
Eggs need turning at least 3-5 times a day from day 1 through day 18 so the developing embryo doesn’t stick to the inside of the shell membrane, which can happen if an egg sits in one position too long. Turning mimics what a broody hen does naturally throughout the day without you having to think about it — an incubator without an automatic turner needs you to do this by hand.
Use an odd number of turns per day (3 or 5, not 4) so the egg doesn’t rest on the same side for two nights in a row — this is standard incubation guidance built around the long overnight gap when nobody’s turning eggs. Mark one side of each egg with a pencil so you can track whether it’s actually been turned, especially in a batch large enough to lose track of by eye.
Turning stops completely at lockdown (day 19). At that point the embryo is orienting itself to hatch, and continued turning can actually work against a chick that’s already positioning for pip.
What Happens During Lockdown?
Lockdown is the final 3 days (day 19-21) before hatch: stop turning eggs, raise humidity to 65-75%, and keep the incubator closed as much as possible so conditions stay stable while chicks pip and hatch. This is the point where a keeper’s instinct to check on things works against the hatch — every time the incubator opens, humidity drops right when the chicks need it most.
- Stop turning. Leave eggs flat in their final position.
- Raise humidity to the lockdown range.
- Resist opening the incubator except briefly if truly necessary. Plan any water refills or checks for before lockdown starts.
- Don’t help a chick out of the shell unless it’s been stuck and clearly struggling for many hours — a chick that pips and then takes a day to fully emerge is usually working through a normal process, not one that needs rescuing.
Once chicks hatch, leave them in the incubator until they’re dry and fluffed — this can take several hours — before moving them anywhere. A wet, newly hatched chick chills fast outside the incubator’s warmth and humidity.
How Do You Know Which Eggs Are Actually Developing?
Candling — holding a bright light behind the egg to see inside — at day 7, day 14, and day 18 shows which eggs are fertile and developing, which are clearly infertile, and which started developing and then stopped (a “quitter”). Doing this before lockdown lets you remove eggs that aren’t going anywhere, which frees up incubator space and reduces the risk of a bad egg affecting the ones around it.
This is detailed enough to deserve its own guide — see candling eggs for exactly what to look for at each of these three checkpoints.
What Do You Do After Chicks Hatch?
Once hatched chicks are dry and fluffed, move them to a pre-warmed brooder set to roughly 95°F (35°C) at chick level and begin the standard brooding routine. Incubation and brooding are two different jobs with two different sets of equipment, and the transition between them is a common point where a keeper who did everything right up to hatch loses chicks to a cold brooder that wasn’t ready in time.
See our pillar guide on how to brood chicks for the full day-by-day plan from that point forward, and our brooding temperature guide for the week-by-week schedule.
The Honest Limits Here
The temperature, humidity, and turning figures here are standard, well-documented incubation ranges that hold across incubator brands and chicken types. What this guide can’t do is tune those ranges to your specific incubator’s quirks — every unit runs slightly differently, and the only way to know yours is to run a few hatches and track results against these numbers. Hatch rate also depends heavily on factors outside incubation itself, like the fertility and freshness of the eggs going in, which this guide doesn’t attempt to quantify.
Once eggs are candled and you know what’s developing, the next milestone is hatch and the move into brooding. See our guides on candling eggs and how to brood chicks to carry the process through, or browse the full brooding and chick-care category for everything in between.
Frequently Asked Questions
How many days does it take to hatch a chicken egg?
21 days from the start of incubation, though a hatch spread across day 19-22 is normal. Not every egg in a batch hatches on exactly the same day.
What temperature should an incubator be set to?
About 99.5°F (37.5°C) for a forced-air incubator with a fan, or 100-101°F (37.8-38.3°C) for a still-air incubator without one. The type of incubator determines which range applies.
What humidity do chicken eggs need during incubation?
Roughly 50-55% for days 1-18, then raised to 65-75% for lockdown on days 19-21. The humidity jump at lockdown helps the chick's membrane stay soft enough to pip through.
How many times a day should eggs be turned?
At least 3-5 times a day, on an odd number of turns so the egg doesn't rest on the same side two nights running, from day 1 through day 18. Turning stops completely at lockdown.
What is lockdown in incubation?
Lockdown is the final 3 days (day 19-21), when egg turning stops, humidity is raised, and the incubator is left closed as much as possible so the chicks can position themselves to hatch.
Why did some eggs not hatch?
Some eggs are infertile from the start, and some stop developing partway through (a "quitter"). Candling at day 7, 14, and 18 identifies both before lockdown — see our candling guide for what each looks like.
Can you open the incubator during lockdown?
Keep it closed as much as possible during lockdown. Opening the incubator lets humidity escape right when the chicks need it most to soften the membrane for pipping.
What happens right after chicks hatch?
Leave newly hatched chicks in the incubator until they're dry and fluffed, which can take several hours, then move them to a pre-warmed brooder — they don't need food or water in the first hours since they're still absorbing the yolk sac.