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Peep & Pen

Optional stage — the 21 days before the brooder

Hatching: the optional stage, and the numbers that decide it

Most first-time keepers should buy day-old chicks. If you are going to incubate anyway, these are the published figures — power draw, capacity, temperature and humidity — rather than the folklore.

Newly hatched chicks and unhatched eggs inside an incubator

Start with the honest version: most people reading this should not incubate. A first flock is easier, cheaper and far more likely to end well if you buy day-old pullets from a hatchery or a feed store. Sexed pullets mean you get hens. Incubating means roughly half of what hatches is male, and in most towns you cannot keep a rooster. That is not a footnote — it is the single biggest reason first hatches end badly, and it happens on day 21, not on setting day.

This hub exists because plenty of people are going to hatch anyway, and because the published information about it is unusually good in one narrow respect and unusually bad in another. The good part is the biology: extension services publish exact temperatures, humidity ranges, turning frequencies and a day-by-day timeline, and those figures do not vary by brand or opinion. The bad part is the machines: of the six incubators covered here, only one maker publishes a full specification sheet, and two publish no specification table at all.

The figures that do not vary by brand

These come from Mississippi State University Extension, and they are the same whatever machine you buy. If a product manual disagrees with them, the manual is describing that machine’s calibration, not the biology.

Published incubation figures for chicken eggs. Source: Mississippi State University Extension.
FactorPublished figureNotes
Incubation period21 daysAll chicks out by the end of day 21
Temperature, forced air100 FHeld throughout
Temperature, still air102 FMeasured at the top of the eggs
Humidity, setting to day 1858 to 60 percent84 to 86 F wet bulb
Humidity, last 3 days65 percent or more89 to 90 F wet bulb
TurningAt least 4 to 6 times dailyStop for the last 3 days
CandlingDays 4 to 7, then 14 to 16Two checks, not one

There is one discrepancy worth knowing about rather than glossing over. Mississippi State Extension publishes 100 F for a forced-air incubator. Brinsea ships every machine on this site factory-preset to 99.5 F. Both figures are published, both are defensible, and the half-degree gap sits well inside the variation of where you put the sensor. We are not going to pick a winner for you; the day-by-day guide shows both and tells you which one your machine is already set to.

What actually decides which machine

Three specifications separate incubators, and price is a poor proxy for any of them.

  • Turning. Manual or automatic. Manual means opening the lid four to six times a day for eighteen consecutive days — about ninety interventions. Automatic means a cradle that also has to know to stop before hatch. The automatic-turner comparison covers what “automatic” actually means on each machine, because the intervals published range from every two hours to every four.
  • Humidity. Almost every machine is manual: you top up a water tray and read a hygrometer. Exactly one incubator here publishes automatic humidity control, and it is the most expensive.
  • Published power draw. This sounds like a minor spec and it is the one that separates makers most sharply. Brinsea publishes typical AND maximum watts on every model. Nobody else publishes a typical figure at all, which means for those machines you can compute a ceiling and nothing better. What a hatch costs to run does that arithmetic with the inputs shown.

Capacity, and the arithmetic nobody does before setting

Egg capacity is the one number every maker publishes, and it is the one most likely to mislead you — not because it is wrong, but because it is a tray count rather than a chick count. Fertility is never 100 percent, not every fertile egg develops, and not every developed egg hatches.

Then halve what is left. Roughly half of any hatch is male. If your ordinance prohibits roosters, and most suburban ones do, a 24-egg machine is a decision to find homes for somewhere around ten cockerels. That is the arithmetic to do on setting day rather than on day 21, and it is the reason how many chickens to start with is worth reading before you buy an incubator rather than after.

What else you need, and what you do not

The genuinely necessary extras are short: a separate thermometer and hygrometer to check the machine against, because a display that reads 99.5 F is reporting its own sensor rather than the air around the eggs; and a candler, which is a bright focused light you hold against an egg to see whether anything is developing. The Farm Innovators machine includes one; most do not.

What you do not need is a second incubator as a “hatcher,” humidity pumps, or any of the accessories sold alongside these machines for a first hatch. And you do not need a brooder plate until day 21 — but you do need it on day 21, which is sooner than most people plan for. Hatched chicks need heat immediately, and the temperature schedule they need is the same one shipped chicks need.

One last thing that is easy to miss: an incubator is not a substitute for a broody hen deciding to do this herself, and it is not a machine you can leave. Power cuts, a cold garage overnight, a water tray you forgot on day 6 — all of these are recoverable if you notice and terminal if you do not. Alarms are the reason to pay more, not the display.

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Everything in this stage · 4 pages

Hatching, page by page

FAQ

Questions people actually ask

Should a beginner incubate eggs or buy chicks?

Buy chicks, for a first flock. Hatcheries and feed stores sell sexed day-old pullets, so you get hens; incubating gives you roughly half cockerels, and most suburban ordinances prohibit roosters. Incubation is a genuinely rewarding second-year project once you already know how to raise chicks and have somewhere for the males to go.

What temperature and humidity do chicken eggs need?

Mississippi State University Extension publishes 100 F throughout for a forced-air incubator, or 102 F for a still-air one, with relative humidity at 58 to 60 percent from setting until three days before hatching, then increased to 65 percent or more for the final three days. Brinsea machines ship factory-preset to 99.5 F, which is a calibration choice inside the same range.

How often do you turn eggs in an incubator?

At least four to six times daily through day 18, per Mississippi State University Extension, and then not at all during the last three days before hatching. Automatic turners handle this; published intervals on the machines here range from every two hours to every four hours, and the good ones stop turning by themselves two or three days before hatch.

How much does it cost to run an egg incubator?

It depends almost entirely on published wattage, and most makers do not publish a typical figure. A Brinsea Mini II at a published 12 watts typical draws about 6 kWh across a 21-day hatch; a 40-watt machine at its rating draws about 20 kWh. Our running-cost page shows the arithmetic with every input, so you can substitute your own electricity rate.

Where the numbers came from

Sources