Chicken Egg Incubation, Day by Day
Chicken eggs take 21 days to hatch in an incubator. The routine is simple: hold steady temperature and humidity, turn the eggs several times a day, candle to check progress, then stop turning and raise humidity for the final three days. Here is the timeline.
Before you start
Set the incubator to about 99.5°F (37.5°C) for a forced-air model and let it stabilize for a day before adding eggs. Aim for roughly 45 to 55 percent humidity for the first 18 days. To get your exact candling, lockdown, and hatch dates from your set date, use the hatch date calculator.
Days 1 to 7: early development
Keep the temperature steady and turn the eggs at least three to five times a day (an automatic turner makes this easy). Around day 7, candle each egg in a dark room. You should see a network of veins and a small dark embryo. Clear eggs with no development can be removed.
Days 8 to 14: growth
Continue turning and holding humidity. Candle again around day 14. The embryo now fills more of the egg and you will see a growing dark mass and a defined air cell at the wide end.
Day 18: lockdown
Stop turning the eggs, raise humidity to about 65 to 70 percent, and close the incubator. This is called lockdown. The chick is moving into hatching position, and opening the lid now lets out the moisture it needs.
Days 19 to 21: hatch
Leave the incubator shut and resist the urge to peek. You may hear peeping and see the first pip, a small crack, then a slow unzipping over several hours. Most chicks hatch on day 21, though a day early or late is normal. Let them dry and fluff up in the incubator before moving them to a warm brooder.
After hatch
Move dry chicks to a brooder at about 95°F for the first week. See the brooder temperature calculator for the right heat by age. Incubation timing and candling stages are described by Mississippi State Extension and Penn State Extension.