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Egg incubator: capacity, turning, humidity and power

By the Plain Prepper editors. Updated 2026-10-18.

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Quick answer

An egg incubator holds eggs at a steady temperature and humidity and turns them until they hatch, about 21 days for chickens. Mississippi State University Extension recommends 100 F in a forced-air incubator, 58 to 60% humidity until the last 3 days, then 65% or more, and turning at least 4 to 6 times a day until 3 days before hatch. Brinsea's Mini II Advance holds 7 hen eggs with automatic turning and manual humidity; the Maxi 24 EX holds 24 with automatic humidity control; the Ovation 28 EX holds 28 with automatic humidity and Brinsea's Induced Dual Airflow. All three have a 3-year warranty.

What an incubator has to control

Mississippi State University Extension names four factors for any bird egg: temperature, humidity, ventilation and turning, and says poor hatches most often come from temperature or humidity that is too high or too low for too long. It recommends 100 F throughout incubation in a forced-air incubator, allowing only minor swings and no more than 1 degree in total; high temperatures are especially harmful.

For humidity, MSU recommends 58 to 60% relative humidity from setting until 3 days before hatch, then 65% or more for hatching. Turn eggs at least 4 to 6 times a day, and stop turning for the last 3 days while the chicks move into hatching position. Keep the incubator closed during hatching. Automatic models handle the turning for you; the EX models here also control humidity.

Three Brinsea incubators compared

Model	Hen eggs	Humidity	Typical power
Mini II Advance	7	Water trays, manual	12 W
Maxi 24 EX	24	Automatic pump	24 W
Ovation 28 EX	28	Automatic	30 W

Figures are from Brinsea's product pages. All three have fans, digital control, automatic turning and a 3-year warranty.

Choosing capacity

Not every egg hatches, so plan on setting more eggs than the chicks you want. Start small if you are new: the Mini II Advance's 7-egg capacity lets you learn the routine of temperature, water and turning without a large loss if something goes wrong. Move up to 24 or 28 eggs once you are hatching for a flock.

Egg size matters too. Brinsea's capacities change with the species: the Maxi 24 EX takes 24 hen eggs but 40 quail or 8 goose-size eggs with its included quadrants, and the Ovation 28 EX needs optional large carriers for goose eggs.

Humidity: manual or automatic

The Mini II Advance holds humidity with water trays you top up from outside, which Brinsea says is not suitable for automatic humidity control. You will need to watch the reading and add water. The Maxi 24 EX and Ovation 28 EX measure humidity and pump water to hold the level you set, which takes much of the guesswork out of the 58 to 60% target and the hatch-time increase MSU describes.

Power and outages

An incubator must run around the clock for about three weeks. Using Brinsea's typical power figures, the Mini II Advance uses about 0.3 kWh a day (12 W x 24 h), the Maxi 24 EX about 0.6 kWh and the Ovation 28 EX about 0.7 kWh. Maximum draw is higher while heating: 20, 40 and 60 W.

That makes a small incubator a reasonable load for a portable power station during an outage; check the station's watt-hour capacity against the daily figure and add margin. MSU notes temperatures that run too cool tend to produce late hatches and too warm early hatches, both reducing the number of chicks, so keep the room steady and the lid closed if power fails.

Setting and turning eggs

MSU says to set eggs large end up, or lying horizontal with the large end slightly raised, and never small end up. If you turn by hand, mark one side of each egg with an X and the other with an O in pencil so you can see that every egg was turned, and handle eggs with clean hands, since oily or dusty hands reduce hatchability. Take extra care during the first week, when embryos are most delicate.

All three Brinsea models turn automatically on a programmable schedule, and the Mini II Advance stops turning 2 days before hatch on its own.

Which one to buy

Choose the Mini II Advance to learn or for small batches. Choose the Maxi 24 EX for automatic humidity in a mid-size unit. Choose the Ovation 28 EX for the largest capacity here and the widest range of egg sizes with optional carriers.

What to look for when you buy

Questions people ask

What temperature should an egg incubator be?

Mississippi State University Extension recommends 100 F in a forced-air incubator and 102 F in a still-air incubator, with no more than 1 degree of total variation.

What humidity do chicken eggs need?

MSU recommends 58 to 60% relative humidity until 3 days before hatch, then 65% or more.

How often should eggs be turned?

At least 4 to 6 times a day, according to MSU, with no turning during the last 3 days before hatching.

How much power does an egg incubator use?

Brinsea lists typical draws of 12 W (Mini II Advance), 24 W (Maxi 24 EX) and 30 W (Ovation 28 EX), or roughly 0.3 to 0.7 kWh a day.

Sources

• Important incubation factors (extension.msstate.edu), Mississippi State University Extension
• Mini II Advance fully digital 7 egg incubator (brinsea.com), Brinsea
• Maxi 24 EX fully automatic 24 egg incubator (brinsea.com), Brinsea
• Ovation 28 EX fully automatic digital egg incubator (brinsea.com), Brinsea

Sources checked 2026-10-18.