How to Incubate Chicken Eggs
The short version
| Incubation temp (forced-air) | 99.5–100°F (37.5–37.8°C) |
|---|---|
| Still-air temp (top of egg) | 100.5–102°F (38.1–38.9°C) |
| Humidity (days 1–lockdown) | 45–55% |
| Humidity (lockdown–hatch) | 65–75% |
| Total incubation | 21 days |
| Lockdown day | Day 18 |
| Candle around | day 7, day 14, day 18 |
Day-by-day schedule
| Day | Phase | What to do | Temp | Humidity |
|---|---|---|---|---|
| Days 1–7 | Incubation | Set eggs large-end up or on their side and turn at least 3–5 times a day (an odd number so they rest on alternate sides overnight), or use an autoturner. Candle around day 7 to confirm a spider-web of veins and a beating heart. | 99.5–100°F | 45–55% |
| Days 8–14 | Incubation | Keep turning and hold temperature steady. Candle to remove clears (infertile) and quitters (blood rings / stalled embryos) so they don't spoil in the incubator. | 99.5–100°F | 45–55% |
| Days 15–17 | Incubation | Final turning days. The chick fills most of the egg; the air cell should be clearly drawn down. Top up water channels so humidity doesn't crash before lockdown. | 99.5–100°F | 45–55% |
| Day 18 | Lockdown | Stop turning. Lay eggs on their side, raise humidity to 65–75%, and keep the incubator closed — opening it now can shrink-wrap chicks. This is 'lockdown.' | 99.5–100°F | 65–75% |
| Days 19–20 | Hatch | Chicks internally pip into the air cell, then externally pip the shell. Expect peeping and small cracks. Resist opening the lid — humidity loss stalls hatching siblings. | 99.5–100°F | 65–75% |
| Day 21 | Hatch | Most chicks zip and hatch. Leave them in the incubator to dry and fluff for several hours before moving to a brooder. Stragglers can arrive on day 22–23, especially from cooler incubators. | 99.5–100°F | 65–75% |
Temperature: forced-air vs still-air
In a forced-air incubator (one with a fan) the whole cabinet sits at one temperature, so set it to 99.5–100°F. Mississippi State University Extension specifies 100°F throughout incubation; other extension sources commonly cite 99.5°F. Either is within the safe band.
A still-air incubator has no fan, so warm air layers near the top. Measure temperature at the top of the eggs and run 100.5–102°F there — Mississippi State cites 102°F for still-air. A still-air unit that reads 99.5°F at egg-top is actually running cold.
Humidity and the air cell
Run 45–55% relative humidity for days 1–18, then raise it to 65–75% at lockdown (Mississippi State Extension cites roughly 58–60% during incubation and 65%+ at hatch). The single best check is the air cell: candle weekly and confirm it is growing to about one-third of the egg by day 18. If the air cell is too small, lower humidity; if it is too large, raise it.
Candling
Candle around day 7–10 to confirm fertility — you're looking for a network of blood vessels and a moving embryo (the egg tooth and distinct wing and leg segments are visible by day 7 per eXtension embryo-development data). Candle again before lockdown to remove clears and quitters so they don't burst and contaminate the hatch.
Calculate your hatch dates
Enter the date you set your chicken eggs to get your candling, lockdown, and hatch dates — with a calendar download.
Pick a species and the date you set the eggs to see your candling, lockdown, and hatch dates.
Dry-hatch vs standard humidity
- The 'dry hatch' method runs lower humidity (roughly 30–40%) through the first 18 days and relies on watching the air cell grow to the right size, then raising humidity hard at lockdown. It suits humid climates or big-air-cell shipped eggs; drier-climate hatchers may need the standard 45–55%.
- Whichever method you pick, the target is the same: the air cell should reach about a third of the egg by day 18. Candle and adjust to the air cell, not to a fixed humidity number.
Shipped eggs
- Let shipped eggs rest large-end up for 8–24 hours before setting so scrambled air cells can re-settle.
- Shipped eggs often hatch at only 50% even when handled well — jostled air cells and temperature swings in transit are the cause, not your incubator. Set more than you need.
- If air cells are wobbly or detached ('saddled'), incubate upright in an egg carton for the first week and hand-turn gently.
Common pitfalls
- Trusting the incubator's built-in thermometer — calibrate against a known-good thermometer and hygrometer first.
- Opening the incubator during lockdown, which drops humidity and can shrink-wrap a pipped chick.
- Chasing a humidity number instead of the air-cell size; too-wet incubation drowns chicks, too-dry sticks them.
- Turning past day 18, which interferes with the chick positioning to pip the air cell.
Frequently asked questions
- What temperature do I incubate chicken eggs at?
- 99.5–100°F in a forced-air incubator, or 100.5–102°F measured at the top of the eggs in a still-air incubator.
- What day is lockdown for chicken eggs?
- Day 18. Stop turning, raise humidity to 65–75%, and keep the incubator closed until the chicks hatch on day 21.
- How long do chicken eggs take to hatch?
- 21 days. A few chicks may hatch on day 22–23, especially if the incubator ran slightly cool.
- What humidity do I need for hatching chicken eggs?
- Around 45–55% for the first 18 days, then 65–75% from lockdown through hatch. Use the air-cell size as your real guide — it should reach about a third of the egg by day 18.
- When should I candle chicken eggs?
- Around day 7–10 to confirm veining and fertility, and again just before lockdown on day 18 to pull any clears or quitters.
- Why didn't my chicken eggs hatch on day 21?
- Cool incubation delays hatching, so give stragglers until day 23 before giving up. Persistent late or failed hatches usually trace to inaccurate temperature, wrong humidity/air-cell size, or shipped eggs with damaged air cells.
Sources
- Important incubation factors — Mississippi State University Extension Service (University extension)
- Avian Embryology (day-by-day embryo development) — eXtension — Poultry (University extension)
- Hatching Quality Chicks (egg storage & handling) — Mississippi State University Extension Service (University extension)