Incubating chicken eggs can be a rewarding way to raise a new flock, but successful hatching depends on consistency. Temperature, humidity, ventilation, egg turning, and timing all work together during the approximately 21-day incubation period. A reliable incubator helps maintain the right environment, but daily observation and careful preparation are just as important.
This guide explains how to incubate chicken eggs from setup through hatch day, including what to do before the eggs go into the incubator and how to prepare for newly hatched chicks.
Choose and Prepare the Eggs
Start with clean, normally shaped, fertile eggs from healthy hens and a suitable rooster. Avoid eggs with cracks, thin shells, heavy staining, or unusual shapes. Very dirty eggs should generally not be washed because washing can remove the shell’s natural protective coating and allow bacteria to enter more easily.
If you are not placing the eggs in the incubator immediately, store them with the pointed end facing down in a cool location away from direct sunlight. Avoid storing them for longer than necessary, and allow refrigerated or cool eggs to gradually reach room temperature before incubation. Sudden temperature changes can create condensation on the shell.
Before setting the eggs, clean the incubator according to the manufacturer’s instructions and place it on a stable, level surface. Keep it away from windows, drafts, heaters, and areas with major temperature changes. Run the empty incubator for at least several hours, and preferably for a full day, so you can confirm that the temperature and humidity remain reasonably stable.
Set the Correct Incubator Temperature
Temperature is one of the most important factors in incubation. For a forced-air incubator with a fan, the commonly used target is 99.5°F (37.5°C). A still-air incubator without a fan may require a higher setting, often around 101°F to 102°F (38.3°C to 38.9°C), measured at the top of the eggs. Always follow the temperature guidance provided with your specific incubator, since sensor placement and design can vary.
Use a dependable thermometer and check that it is positioned correctly. A temperature that is too high can speed development and cause embryos to develop improperly, while a temperature that is too low can delay development and hatching. Short fluctuations may happen when eggs are turned or the lid is opened, but repeated or prolonged swings should be corrected.
Once the eggs are inside, resist the temptation to adjust the controls constantly. Make small changes, allow the incubator time to respond, and monitor conditions at regular intervals. Keeping a simple record of temperature, humidity, turning, and observations can make the process easier to manage.
Manage Humidity Throughout Incubation
Humidity controls how much moisture the eggs lose through their shells. For many chicken eggs, a relative humidity range of approximately 40% to 50% works well during the first 18 days. The exact target may need to vary with your incubator, local climate, and egg characteristics.
Humidity is usually adjusted by adding water to one or more reservoirs in the incubator. Add water gradually rather than filling every channel automatically. Opening the incubator too often can cause unnecessary changes, so check the water level through a viewing window when possible.
Egg appearance can also provide useful clues when candling. The air cell should gradually increase as the egg loses moisture. If the air cell appears too small, humidity may be too high; if it appears unusually large, humidity may be too low. These observations are helpful, but they should be considered alongside the incubator’s humidity reading and the manufacturer’s guidance.
Turn the Eggs Regularly
Turning helps prevent the developing embryo from settling against the shell membrane. During the first 18 days, turn the eggs at least three times per day, with five turns often being a practical routine when turning by hand. An automatic turner can make the schedule easier and more consistent.
Mark each egg with a pencil using an “X” on one side and an “O” on the other. This makes it easy to see whether each egg has been turned. Do not use ink, paint, or markers that may affect the shell.
Turn the eggs gently and avoid shaking them. If turning by hand, change direction each time and handle the eggs with clean, dry hands. Stop turning at the beginning of day 18. This period is often called lockdown, because the chicks are moving into position for hatching and the incubator should remain closed as much as possible.
Candle the Eggs at the Right Time
Candling means shining a bright light through the egg in a dark room to observe development. A first check around day 7 can reveal veins and a developing embryo in fertile eggs. A second check around day 14 can help you assess continued growth and remove eggs that are clearly not developing.
Hold the egg over the light briefly and return it to the incubator promptly. Developing eggs may show a network of veins, a darkening embryo, and movement. Clear eggs may be infertile or may have stopped developing. Because development can be difficult to interpret, avoid discarding an egg based on one uncertain observation. If in doubt, mark it and check again several days later.
Remove cracked eggs or eggs that leak, smell unpleasant, or show signs of spoilage. A spoiled egg can contaminate the incubator and the other eggs. Clean any affected area according to the incubator manufacturer’s instructions.
Prepare for Lockdown and Hatching
On day 18, complete the final turning and make the incubator ready for hatch. Stop turning, place the eggs on a flat hatching surface if necessary, and raise humidity. A common lockdown target is approximately 65% to 70% relative humidity, although your incubator’s instructions may recommend a different range.
Higher humidity during hatching helps keep the membranes from drying as the chicks begin to break through the shell. Avoid opening the incubator unnecessarily during this stage. Each opening can allow warm, humid air to escape, which may make hatching more difficult for chicks that are already pipped.
Hatching is not always quick. A chick may make a small hole, rest for several hours, and then continue working its way around the shell. It is normal for eggs to hatch at different times, even when they were set together. Avoid helping a chick out of the shell unless you have specific experience and understand the risks; premature assistance can cause bleeding or other complications.
What to Do When the Chicks Hatch
Allow newly hatched chicks to remain in the incubator until they are dry, alert, and fluffy. This often gives the remaining eggs time to hatch without repeated lid openings. Once the chicks are dry and the hatch is complete, move them to a clean, warm brooder.
Before hatch day, prepare the brooder with:
- A secure enclosure with good airflow and enough room for the chicks to move away from the heat
- A reliable brooder heat source with a warm area and a cooler area
- Dry, nonslip bedding such as paper towels during the first few days
- A shallow chick waterer that helps reduce the risk of drowning
- Age-appropriate chick starter feed
A dedicated brooder box starter kit can simplify the transition by providing a contained brooding space along with basic equipment such as a feeder, waterer, perch, and brooder plate. Regardless of the setup you choose, check the chicks frequently and make sure they can move comfortably between warmer and cooler areas.
Common Incubation Problems to Avoid
Many incubation issues come from small inconsistencies rather than one dramatic mistake. Avoid placing the incubator in a drafty location, overfilling water reservoirs, or opening the lid repeatedly to check progress. Do not rely solely on a built-in display if the readings seem questionable; a second, accurate thermometer and hygrometer can help confirm conditions.
Other common problems include forgetting to stop turning at day 18, failing to maintain adequate ventilation, and setting eggs that were stored improperly or have damaged shells. Ventilation becomes increasingly important as embryos grow, so keep the incubator’s air vents open as directed rather than sealing the unit to retain humidity.
Finally, follow the manufacturer’s instructions for your particular incubator. Features such as fan placement, automatic turning angles, water channels, and humidity sensors can affect the best settings.
A Simple 21-Day Incubation Schedule
- Before day 1: Select suitable eggs, clean and test the incubator, and stabilize the temperature and humidity.
- Days 1–7: Maintain the recommended temperature, manage moderate humidity, and turn the eggs regularly.
- Day 7: Candle the eggs briefly to check for early development.
- Days 8–14: Continue turning, monitor water levels, and maintain steady ventilation.
- Day 14: Candle again if desired and remove eggs that are clearly spoiled or not developing.
- Day 18: Stop turning, increase humidity for lockdown, and avoid unnecessary opening of the incubator.
- Days 19–21: Watch for pipping and hatching while keeping the incubator closed as much as possible.
Final Tips for a Successful Hatch
Successful incubation is mostly about preparation and stability. Start with suitable eggs, test the incubator before setting them, and use accurate measurements for temperature and humidity. Turn the eggs consistently through day 17, stop turning at lockdown, and give hatching chicks time to work out of their shells naturally.
Keep notes throughout the process so you can identify what worked and make informed adjustments for the next hatch. With careful monitoring and a properly prepared brooder, incubation can lead smoothly from fertile egg to healthy, active chick.