Why Eggs Don't Hatch: Failure Causes by Day (Day 1 to 21+)

Many people feel excited when they start hatching eggs. They expect every egg to hatch. That often does not happen. Egg hatching problems are common, even for experienced keepers. Some eggs stop growing early. Others reach the final days but never hatch. These failures can feel confusing and disappointing.

Tracking egg development day by day helps you understand what went wrong. Each stage of growth has clear signs. When you know what should happen on each day, you can spot problems faster. This makes it easier to fix incubation problems before it is too late.

Eggs may not hatch for many reasons. The eggs may not be fertile. The temperature may be too high or too low. Humidity may stay off for too long. Eggs may not get turned often enough. Poor airflow can also prevent eggs from hatching.

Beginners often face extra challenges. Many open the incubator too much. Some guess the settings instead of checking them. Others do not candle eggs at the right time. These small mistakes can lead to problems with hatching chicken and duck eggs.

This guide explains egg hatching problems from day 1 to day 21, and what to do when eggs run past it. You will learn what healthy growth looks like each day. You will also learn why eggs fail at each stage. By the end, you will know how to read the signs and improve your next hatch.

How Egg Development Works (Quick Overview)

Egg growth follows a clear pattern from start to hatch. This process is called egg development. Each day matters. An early issue can cause egg-hatching problems later.

Chicken and duck eggs grow at different speeds:

• Chicken eggs usually hatch in about 21 days.
• Duck eggs often take closer to 28 days.

Because of this, chicken egg development day by day moves faster than duck egg development day by day.

Chicken and duck egg hatching problems differ:

• Chicken eggs react quickly to heat changes
• Duck eggs need more moisture during growth

Using the same settings for both often leads to incubation problems.

Three factors control healthy growth:

• The temperature must stay steady.
• Humidity must match the growth stage
• Eggs must be turned often

When these stay correct, eggs grow well and hatch on time.

Settings at a Glance

For other species and still-air incubators, see our egg incubator temperature and humidity chart, and our humidity control guide for how to adjust it.

Day by Day: Chicken vs Duck

Duck eggs run about a third longer, so the same stages land on later days. Use this table to find where a duck egg should be.

For duck eggs specifically, read our duck egg incubation guide for temperature, humidity and hatch time.

Days 1 to 3: Early Development Failures

The first three days are the most important. Many eggs fail at this stage. Most early egg hatching problems come from fertility or setup mistakes.

What Should Happen

During this stage, growth begins inside the egg.

For chicken eggs:

• Growth starts within the first day
• The heart begins to beat around day two
• Blood vessels begin to form, though you usually can't see them by candling until around day four

This early development in a chicken egg lays the foundation for a complete hatch.

For duck eggs:

• Growth follows the same steps
• Changes appear more slowly
• Signs of life are harder to see early

This is normal for duck egg development.

Common Egg Hatching Problems

Early failures often arise from simple issues.

• Eggs are not hatching due to infertility
• Incorrect incubator temperature
• Poor egg storage before incubation

Even minor errors at this stage can stop growth.

Signs of Failure

It is hard to judge eggs this early, because candling in the first three days shows little. Plan your first candling for around day 4 to 7 (day 7 for dark shells).

• Clear eggs at your first candling, which means infertile or died very early
• No visible blood vessels at day 7

These signs show that the egg stopped growing during the first few days.

Days 4 to 7: Blood Vessel Growth Problems

Days four to seven are a key growth period. During this time, blood vessels spread across the egg. These vessels carry oxygen and nutrients to the embryo. Many egg-hatching problems at this stage are linked to oxygen deprivation and rough handling.

Normal Development

Healthy eggs show clear signs of growth.

• Delicate veins spread across the inside of the egg when candled.
• The embryo starts to move inside the egg.

These signs indicate that egg development is progressing in the right direction.

Incubation Problems at This Stage

Growth can stop quickly if conditions change.

• Sudden embryo death from poor airflow
• Shaking or rough egg handling
• Poor ventilation inside the incubator
• A thin red ring (a blood ring) inside the egg. This usually means the embryo died early, so check your temperature log for a swing or a power loss in the first week.

Embryos need fresh air. Without it, growth slows or stops.

Chicken vs Duck Differences

Chicken and duck eggs grow at different speeds.

• Chicken embryos grow faster during these days
• Duck embryo growth stays slower and steadier

This is normal and should not cause concern if other signs look healthy.

Days 8 to 10: Mid Incubation

Days eight to ten mark the middle of incubation. At this point, the embryo grows larger and stronger. Most egg hatching problems here arise from heat or moisture issues.

What Healthy Eggs Show

Candling should show strong growth.

• Thick and strong veins
• A dark embryo shape fills more of the egg

These signs show healthy chicken egg development day by day and duck egg development day by day.

Common Causes of Failure

Several problems can stop growth at this stage.

• Overheating eggs for long periods
• Low humidity that dries the embryo
• Poor egg turning that limits growth

These issues often build up over time.

Key Egg Hatching Problems

Some signs point to mid-stage failure.

• An embryo that has not grown since your last candling
• Faint or broken veins, or a dark mass that no longer moves
• Weak embryo growth

These signs often mean the embryo died during mid-incubation.

Days 11 to 14: Growth but No Strength

Days 11 to 14 show rapid growth. The embryo appears large but may be weak. Many egg-hatching problems here are linked to egg quality and parent health.

Expected Development

Healthy eggs show evident progress.

• Feathers begin forming on the embryo.
• The embryo fills most of the egg

These signs show strong egg development day by day.

Why Eggs Stop Developing

Growth may slow or stop for several reasons.

• Weak parent stock that produces poor eggs
• Shells that are too thin or too thick
• Prolonged incubation without proper turning

These problems limit oxygen and movement inside the egg.

Chicken Egg Hatching Problems vs Duck Eggs

Chicken and duck eggs differ in their reactions.

• Duck eggs need higher humidity to stay healthy
• Chicken eggs are more sensitive to heat swings

Using inappropriate settings can cause delayed growth failure.

Days 15 to 17: Late Stage Development Failures

This stage prepares the chick for hatching. The embryo assumes position and develops strength. Many failures are now linked to airway and body position.

Normal Signs

Healthy eggs show fewer movements.

• Movement becomes limited as the chick fills the egg
• The chick turns its head toward the air cell. The internal pip into the air cell happens a little later, around day 19 to 20.

This is a normal part of chicken and duck egg development, day by day.

Egg Hatching Problems at This Stage

Late failures often come from setup issues.

• Chicks positioned incorrectly inside the egg
• Low oxygen levels in the incubator
• Dirty airflow that blocks fresh air

These issues weaken the chick before hatch time.

Days 18 to 19 Lockdown Mistakes

Lockdown starts on day 18 for chicken eggs (day 25 for duck eggs) and runs until hatch. Days eighteen and nineteen are when small mistakes begin to cost you the hatch.

What Should Change

Two essential steps happen during lockdown.

• Stop turning eggs
• Increase humidity to about 65 to 70% to soften membranes

These steps help chicks break out of the shell.

Common Incubation Problems

Many eggs fail due to simple errors.

• Opening the incubator too often
• Incorrect humidity spikes
• Eggs do not hatch due to membrane desiccation.

Dry membranes impede chicks' ability to escape.

Days 20 to 21: Pipping but No Hatch

These are the final days of incubation. Many chicks reach this stage but still fail to hatch.

Normal Hatch Process

A healthy hatch follows a clear order.

• Internal pip into the air cell (usually day 19 to 20)
• External pip through the shell
• Zipping and hatching

Each step takes time and strength.

Why Chicks Fail to Hatch

Several problems can stop the final hatch.

• Shrink-wrapped membranes
• Weak chicks that lack energy
• Assisting too early or too late

Helping at the wrong time can cause more harm.

Chicken vs Duck Hatch Timing

Hatch timing differs by species.

• Chickens hatch sooner
• Ducks may need extra days

Waiting longer is often normal for duck eggs.

Eggs Not Hatching After Day 21? How Long to Wait

If day 21 has passed and nothing has hatched, don't open the incubator yet. Chicken eggs set in a slightly cool incubator, eggs that were stored for a week or more, or a wrong set date can all push hatching back by a day or two.

• Chicken eggs: keep the incubator closed and wait until about day 23 to 24 before deciding the rest won't hatch.
• Duck eggs: wait until about day 30. Muscovy duck eggs run longer, about 35 days.
• First, check your set date. Count again from the day you actually set the eggs, not the day you collected them.
• Look at your temperature log. A run of cool readings explains a late hatch. A run of hot readings can cause an early hatch of weak chicks.

After the waiting time has passed: candle the remaining eggs. Eggs with no movement, a dark mass, a blood ring, a bad smell, or a leaking shell are dead and should be removed. A rotten egg can burst and contaminate the rest, so remove it carefully and disinfect the incubator. If an egg has pipped but made no progress for a full day, see our beginner's guide to hatching eggs before deciding whether to help.

Likely Cause by Symptom

• Clear eggs at first candling: infertile, or died in the first days.
• Blood ring: embryo died early. Check for a temperature swing or power loss in week one.
• Fully formed chick, dead and never pipped: humidity or temperature problems late in incubation, or poor ventilation.
• Chick pipped but did not hatch: membranes dried out because humidity was too low during lockdown, or the incubator was opened too often.
• Hatching late and weak: incubator ran cool. Hatching early and weak: ran hot.
• Power outage: read our guide on what to do if the power goes out during incubation.

Chicken vs Duck Egg Hatching Problems

Chicken and duck eggs have different needs during incubation. Knowing these differences helps reduce egg hatching problems. The table below shows the key points side by side.

How to Reduce Egg Hatching Problems

Good habits can improve hatch results.

• Use fresh and fertile eggs only.
• Maintain a stable temperature at all times
• Track egg development day by day
• Candle eggs correctly to check growth (see our egg candling guide)
• Keep the incubator clean and dry
• Check your readings against a second gauge, and use our egg incubator setup guide to make sure the basics are right before you set eggs

Small changes can prevent many eggs from hatching.

Learn From Each Hatch

Hatching failures happen to everyone. Even skilled keepers lose eggs. What matters most is learning from each hatch. Watching growth closely improves results over time. Each failed hatch yields valuable insights and helps improve the next one. Once chicks do hatch, our baby chick care guide covers the first days.

FAQs (People Also Ask)

Q: Why do some eggs stop growing after the first week?

Ans: This often happens due to poor airflow, low humidity, or weak embryos. Early stress can stop growth.

Q: Can eggs hatch if the temperature is wrong for one day?

Ans: Short changes may not kill the embryo. Long or repeated heat issues often cause failure.

Q: How often should eggs be turned during incubation?

Ans: Eggs should be turned several times each day until the lockdown. Turning helps even growth.

Q: Is candling too often bad for eggs?

Ans: Brief candling is safe. Candle two or three times during incubation, keep each egg out for only a minute or so, and work in a warm room so eggs don't cool.

Q: Why do eggs smell bad during incubation?

Ans: A bad smell usually means the egg has died and started to rot. Remove it right away.

Q: Can dirty eggs still hatch?

Ans: Dirty eggs have a higher risk of bacteria. Clean eggs have better hatch success.

Q: Why do chicks die just before hatching?

Ans: Late death often comes from low humidity, poor oxygen, or weak chicks.

Q: Do older eggs have lower hatch rates?

Ans: Yes. Eggs stored too long lose moisture and strength, which lowers hatch success.

Q: Can power loss ruin a hatch?

Ans: Short power loss may not harm eggs. A long loss can cause serious incubation problems. See our power outage guide for what to do.

Q: What if my eggs have not hatched by day 21?

Ans: Wait before giving up. Chicken eggs can hatch a day or two late, and duck eggs run to about day 28 to 30. See the section above on how long to wait.

Q: Is it normal if only half the eggs hatch?

Ans: Hatch rates vary, and first-time hatchers often see lower results. If fewer than about half of your fertile eggs hatch, work through the day-by-day checks above to find what needs fixing.