Chicken egg incubation day by day: what to expect and do each day

Part of our guide on heated chicken waterer

A clear daily chicken incubation schedule with exact temperature, humidity, and turning care for every stage.

Incubation period length and temperature requirements

Chicken eggs incubate for exactly 21 days under consistent conditions.

Optimal temperature is 99.5°F (±0.5°F) throughout incubation to ensure embryo viability.

Humidity must start at 50-55% and increase to 65-70% from day 18 to prevent membranes from drying.

Temperature fluctuations over 1°F can reduce hatch rates significantly. If that sounds like your situation, read up on tracking egg hatch timing next.

Incubation temperature must remain steady because embryos cannot regulate their own heat. A 0.5°F drop below 99.5°F for two days can slow development by a day or more. Conversely, a rise above 100°F may cause deformities or death. Use a calibrated thermometer to check incubator readings twice daily. Avoid opening the incubator often since it causes temperature drops and humidity shifts that stress the embryos.

Humidity also affects water loss from the egg. Too low, and the chick can become dehydrated inside the shell. Too high, and the chick may drown in fluid or fail to absorb the air cell needed for breathing before hatching. Weighing eggs daily can track water loss; normal loss is about 12-15% of egg weight by day 18. If weight loss is outside this range, adjust humidity accordingly.

Development milestones by day during chicken incubation

Embryo development follows a precise timeline essential for monitoring. Before you commit to anything, it is worth looking at preparing eggs for hatching.

By day 3, the embryo forms a heartbeat visible via candling.

Day 7 shows limb buds and blood vessel network expanding clearly.

By day 14, feathers and beak start forming; the embryo looks distinct. If that sounds like your situation, read up on health effects of daily chicken next.

Day 18 marks the embryo turning head toward air cell preparing to hatch.

The embryo's heartbeat, visible by candling on day 3, pulses at around 90-110 beats per minute. If no heartbeat appears by day 5, the egg is likely infertile or the embryo has died. Limb bud growth between days 5 and 7 happens rapidly; missing or asymmetrical limbs indicate problems. Feather germs start forming on day 13 and become visible by day 14, signaling healthy feather development. The embryo rotates inside the egg up to day 18 to position for hatching; failure to turn properly can cause malformations.

Daily turning and humidity needs during incubation

Turn eggs 3-5 times daily to stop the embryo from sticking to the shell membrane. The other half of this decision is daily chicken egg logging app.

Stop turning eggs on day 18 to let the chick position for hatching.

Maintain humidity at 50-55% during the first 17 days to prevent dehydration.

From day 18, increase humidity to 65-70% to soften the shell for easier pipping. We go through treatment steps for sick birds step by step elsewhere on the site.

Use automatic turners if possible to ensure consistent turning.

Turning eggs prevents the embryo from sticking to the shell membrane and promotes even heat distribution. When turning, tilt the eggs at least 45 degrees from each side. Mechanical turners are recommended for large batches to ensure consistent, frequent movement. After day 18, the embryo starts absorbing the yolk sac and positions its head toward the air cell; turning must stop to avoid injury. Humidity control can be achieved by adjusting water trays or using a hygrometer to monitor levels closely.

• Turning: at least 3 times daily, ideally 5 times
• Humidity: 50-55% until day 17, then 65-70%
• Stop turning after day 18
• Raise humidity at hatching phase

What happens on day 21 of chicken incubation

Day 21 is hatch day: chicks pip and emerge from the shell.

Humidity must be at the higher range, 65-70%, to assist membrane softening.

Temperature should stay steady at 99.5°F to maintain development pace.

Avoid opening the incubator to keep humidity and temperature stable.

Chicks may take 24 hours to fully hatch after first pip.

On day 21, chicks begin pipping by breaking the inner shell membrane with their egg tooth before cracking the outer shell. This process can last 12 to 24 hours and requires patience. Opening the incubator during this time causes humidity to drop, drying the membranes and making it harder for chicks to hatch. Observe quietly from a distance. After hatching, allow chicks to dry and fluff up inside the incubator before moving them to a brooder.

Common incubation issues and challenges at different days

Poor humidity before day 18 can cause embryo dehydration and early death.

Excess humidity early on leads to drowning embryos or malformed chicks.

Temperature fluctuations cause developmental delays or dead-in-shell embryos.

Stopping turning too early causes embryos to stick to the shell membrane.

Candling failures can miss infertile or dead eggs, risking contamination.

Candling eggs regularly helps detect early deaths or infertile eggs, which should be removed promptly to avoid contamination. A common mistake is fluctuating temperatures after day 10, leading to embryo deformities evidenced by curled toes or twisted necks seen during candling. Excessive humidity in the first two weeks causes embryos to drown, which shows as blood rings or foul smells on candling. Stopping turning too soon leads to the embryo sticking to the shell membrane, visible as dark patches on candling and resulting in failed hatches.

• Early dehydration: low humidity before day 18
• Drowning risk: high humidity too soon
• Temperature swings: avoided by steady heating
• Turning mistakes: stop only after day 18
• Candling: essential for removing bad eggs

Chicken incubation schedule day by day: step-by-step guide

Use this daily schedule to manage key care and milestones during incubation.

Starting day 1, set incubator to 99.5°F and 50-55% humidity.

Turn eggs 3-5 times daily until day 18 and candle on days 3, 7, 14 to check progress.

From day 18, stop turning and raise humidity to 65-70%.

Keep stable temperature and humidity until chicks hatch around day 21.

1. Day 1-2: Set temperature to 99.5°F, humidity 50-55%, start turning eggs 3-5 times daily.
2. Day 3: Candle eggs, remove infertile ones.
3. Day 4-7: Continue turning and maintain temperature/humidity.
4. Day 7: Candle again to check development.
5. Day 8-14: Turn eggs, keep stable conditions.
6. Day 14: Candle and assess embryo growth.
7. Day 15-17: Keep conditions stable, continue turning.
8. Day 18: Stop turning; increase humidity to 65-70%.
9. Day 19-21: Maintain conditions, prepare for hatch.
10. Day 21: Hatch day; avoid opening incubator.

Questions people still ask

I've incubated dozens of chicken batches, learning the value of daily precise care for a full hatch.