Hatching Eggs at Home: Incubator Temperature, Humidity and Turning

Hatching your own Speckled Sussex chicks is one of the most satisfying things a poultry keeper can do. It is also a lesson in patience and detail. Eggs are living things, and a few degrees of temperature, a missed turning or a dirty egg can turn a good hatch into a disappointment. The good news is that incubating is not complicated if you follow a routine.

This guide covers selecting eggs, setting up an incubator, the temperature and humidity guidelines commonly recommended, turning, candling, lockdown and hatch day. Incubator brands differ, so follow the manufacturer's instructions, and use extension resources for details. If you want to find hatcheries and poultry meetings near you, agriculture.directory can help you find agriculture events in your area.

Start With Good Hatching Eggs

A good hatch starts with fertile eggs from healthy, well-fed hens with a rooster. Pick clean, normal-shaped eggs of average size, avoiding cracked, misshapen or very large or small eggs. Collect eggs often, store them pointed end down at a cool room temperature, and set them within about a week or so of laying, since hatchability drops with age. Do not wash hatching eggs if you can avoid it, since washing can remove the protective coating, and gently brush off dirt instead. The eXtension poultry community and University of Minnesota Extension have egg handling and incubation guidelines.

Set Up the Incubator First

Run your incubator for at least a day before setting eggs, so you can check that the temperature is stable and make adjustments. Place it in a room with stable temperature, away from drafts, direct sun and vents. Use an accurate thermometer and a hygrometer, and do not rely entirely on the built-in display.

Temperature

Commonly recommended temperatures are about 99.5 degrees Fahrenheit for forced-air incubators, measured at the level of the eggs, and slightly higher, around 100 to 102, for still-air incubators, depending on where it is measured. Check your incubator's instructions. Temperature is the most important variable. A few degrees too high or too low can ruin a hatch. Avoid opening the incubator more than necessary.

Humidity

Humidity affects how much moisture eggs lose during incubation. A commonly recommended range is about 40 to 50 percent relative humidity for the first 18 days, and about 65 percent or higher during the last three days, called lockdown, though recommendations vary. Add water to the incubator's reservoir as needed, and monitor with a hygrometer. Too little humidity can cause chicks to stick in the shell, and too much can cause weak, wet chicks.

Turning

Eggs need to be turned several times a day, at least three times and often five or more, through about day 18, to keep the embryo from sticking to the shell membrane. Many incubators have automatic turners. If you turn by hand, mark one side of each egg with a pencil so you can see that every egg has been turned, and turn an odd number of times each day so the eggs alternate sides overnight. Wash hands before handling eggs, and be gentle.

Candling

Candling means shining a bright light through an egg to see what is inside. Many keepers candle around day 7 to 10 to check for development, and again around day 14 or 18. A fertile egg shows dark spots and a network of blood vessels, while an infertile egg stays clear. Remove eggs that are clearly infertile or that show a blood ring or foul smell, since a rotting egg can burst and contaminate others. Candle quickly in a dark room, and avoid cooling the eggs.

Lockdown: Days 18 to 21

Around day 18, stop turning the eggs, raise humidity and avoid opening the incubator. The chicks position themselves to hatch and begin to pip, which means breaking through the shell. Hatching can take many hours. Resist the urge to help, since opening the incubator drops humidity and can cause chicks to stick to a dried membrane. Unless a chick is clearly in distress for a long time, let it work.

Hatch Day

Hatching typically takes place on or around day 21, though timing varies by a day or so. Chicks emerge wet and exhausted, and then dry and fluff. Leave them in the incubator until they are dry and active, which can take up to a day, since they live on yolk absorbed before hatching and do not need food or water right away. Then move them to a prepared brooder with heat, starter feed and water.

Biosecurity and Cleaning

Clean and disinfect the incubator between hatches to prevent disease. Wash hands before and after handling eggs and chicks, since poultry can carry Salmonella, as noted in the eXtension poultry articles and CDC guidance. Dispose of unhatched eggs safely.

Why Hatches Go Wrong

• Temperature swings. Check stability and calibrate thermometers.
• Wrong humidity. Measure, do not guess.
• Old or poorly stored eggs. Hatchability declines with time.
• Poor breeder nutrition. Hens need a complete diet to produce good eggs.
• Not turning eggs. Embryos may stick.
• Opening the incubator during hatch. Humidity drops.
• Inbreeding or low fertility. Check the breeding flock.

Record Keeping

Keep notes on set date, egg source, temperature, humidity and results. After a few hatches, patterns show up, and you can improve. For a laugh about what the hens think of all this work, farm.fm has a humor piece on farm eggs finally winning Employee of the Month.