How to use an egg incubator: day-by-day hatching guide

Watching chicks hatch is one of the best parts of keeping chickens. Success depends on five factors that University of Illinois Extension lists in its incubation and embryology guide: fertile eggs, temperature, humidity, ventilation and turning. This guide covers each one, a day-by-day timeline, and what to look for when choosing an incubator.

Types of egg incubators

Type	How it works	Pros	Cons
Still-air	No fan; heat rises	Cheap, simple	Temperature varies by height; measure at egg level
Circulated (forced) air	Fan spreads heat evenly	More even temperature, larger capacity	Costs more; dries eggs faster
Manual turn	You turn eggs by hand	Cheap	Must turn several times daily
Automatic turner	Turns eggs on a schedule	Consistent; less work	Must be removed or stopped for lockdown
Cabinet incubator	Large, multiple trays	Big hatches	Expensive, needs space

How to choose the best egg incubator

• Capacity: buy for the number of eggs you will really set.
• Forced air for more even temperature.
• Automatic turning if you cannot turn eggs three or more times a day.
• Reliable thermostat and an easy-to-read display.
• Humidity control: water channels or an automatic humidity pump.
• Clear window to watch without opening.
• Easy to clean between hatches.
• Spare parts available.

Whatever you buy, add a separate calibrated thermometer and hygrometer. Illinois Extension recommends two thermometers.

Incubator settings at a glance (chicken eggs)

Factor	Days 1–17	Days 18–21
Temperature	99–100°F	99–100°F
Humidity (Illinois wet-bulb guide)	~60% RH (87°F wet bulb)	~70% RH (90°F wet bulb)
Turning	Odd number of times daily, at least 3	Stop — no turning
Opening the incubator	Briefly, for turning and candling	Avoid

Day-by-day timeline

Day	What to do
–2 to 0	Set up incubator in a 70–75°F, draft-free room; run and adjust slowly over 2-hour periods
0	Set eggs warmed to room temperature (30 min–2 hrs); mark X and O with pencil
1–2	Expect a temperature dip after setting; do not raise heat in the first 48 hours
1–17	Turn odd number of times daily; check temperature and humidity; log them
6–10	Candle once, quickly (eggs out no more than about 5 minutes)
End of 17	Stop turning; raise humidity (add sponges or water as the manual says)
18–21	Lockdown: keep closed
~21	Hatch; leave chicks until dry and fluffy
~21–22	Move chicks to the brooder
60 hours after first hatch	Illinois Extension suggests removing and discarding unhatched eggs

Candling

Candling shines a bright light through the egg in a dark room. Between days 6 and 10 you should see veins and a dark embryo in fertile eggs. Clear eggs are likely infertile. Keep candling quick and gentle, wash hands before and after, and do not overheat eggs with the light.

Hatch day

Chicks pip (break the shell), rest, then “zip” around the shell. This can take many hours. Resist helping unless your experience or an expert says it is necessary — opening the incubator drops humidity and can shrink-wrap other chicks in their membranes.

The brooder

Illinois Extension suggests about 85–90°F in the brooder at first, adjusting the lamp height. Provide bedding, chick starter, a shallow waterer and a draft guard. Watch chick behavior to adjust heat.

Why didn’t my eggs hatch?

Problem	Possible cause
Many clear eggs	Infertile eggs; old or poorly stored eggs
Early deaths	Temperature too high or too low; eggs stored too long
Fully formed chicks that did not pip	Humidity too low or too high; temperature problems; turning stopped too late
Sticky chicks	Humidity issues; temperature too low
Early hatch	Temperature too high
Late hatch	Temperature too low

Hygiene

Chicks and eggs can carry Salmonella. The CDC recommends washing hands after handling chicks, eggs or equipment, not letting children under 5 handle chicks, and keeping poultry out of the house. In classrooms, supervise hand washing closely.

Incubator checklist

• Incubator cleaned and disinfected (Illinois suggests 1 teaspoon bleach per gallon of water, or mild soap)
• Two thermometers and a hygrometer
• Running steadily for 1–2 days before setting
• Fresh fertile eggs, unwashed, at room temperature
• Turning schedule or automatic turner set
• Log sheet for temperature, humidity and turns
• Brooder ready before day 18

Where to get hatching eggs

• Your own flock with a rooster
• Local breeders (ask about flock health and testing)
• Hatcheries that sell hatching eggs

Shipped eggs often hatch less reliably than local eggs because of handling and temperature changes. Let shipped eggs rest, pointed end down, before setting, as the seller advises.

Incubation log template

Day	Temp (°F)	Humidity (%)	Turns	Notes
1				Set eggs
2
…
7				Candling
17				Stop turning; raise humidity
21				Hatch

Recording readings at the same times each day makes problems easy to spot.

Hatching projects with children

Classroom and family hatching projects are popular. Plan ahead: decide where chicks will live after hatching, assign daily care, supervise hand washing every time children touch eggs, chicks or equipment, and keep children under 5 from handling chicks, as the CDC advises. Illinois Extension’s guide also suggests putting a sign on classroom incubators so no one unplugs them.

After the hatch

Clean and disinfect the incubator, record your hatch rate and notes on what worked, and keep chicks in a brooder until they are feathered and the weather allows a move to the coop. See backyard chickens for beginners for the next steps.

Calibrating your thermometer and hygrometer

Incubator displays can be off by a degree or more — enough to hurt a hatch. Illinois Extension recommends calibrating or buying a more reliable thermometer and using two. A simple check is to compare your thermometers with a trusted reference thermometer at the same spot. For hygrometers, the wet-bulb method in the Illinois guide (a cotton wick on a thermometer bulb in the water channel) is an inexpensive cross-check.

Ventilation during incubation

Embryos need oxygen and release carbon dioxide. Illinois Extension notes that vent holes allow oxygen in and carbon dioxide out, and suggests removing one vent plug during the hatch and both after chicks have hatched in the incubators it describes. If condensation forms inside the window, removing a plug can help. Always follow your model’s instructions.

Common incubation mistakes

Mistake	Fix
Setting eggs before the incubator is stable	Run it 1–2 days first
Raising the heat after the initial drop	Wait 48 hours; temperature recovers
Opening the incubator during lockdown	Keep it closed from the end of day 17
Washing hatching eggs	Do not wash; lightly sand dirty spots
Even number of turns	Turn an odd number of times
Placing the incubator near a window	Choose a draft-free spot at 70–75°F

Bottom line

Stable temperature, the right humidity, regular turning until day 17 and a closed incubator during lockdown are the keys to a good hatch. Test your equipment before setting eggs, log readings daily and learn from every hatch: hatch rates usually improve with experience. Plan the brooder and the chicks’ future home before the eggs go in, so hatch day is a celebration rather than a scramble. Keep notes on every setting and result, and compare hatches over time to find what works best with your incubator and your eggs. Each hatch teaches you something new. Enjoy hatch day and the chicks that follow.

Hatching other poultry

Ducks, turkeys, guinea fowl and quail need different incubation lengths, humidity and sometimes temperatures from chickens. Use species-specific guidance from your incubator manual or an extension publication, and buy turner rails sized for the eggs you plan to hatch.

Planning tools

The Backyard Coop & Incubation Guide has a 21-day incubation calendar, an incubation log and a “why didn’t my eggs hatch?” checklist. Hatching quail instead? Read raising quail. More in backyard chickens for beginners and the backyard chickens and quail guide.