Egg Candling Day-by-Day Photo Guide for Air Cell Growth and Red Flags

When you start egg candling, always work in complete darkness and use a bright LED at the large end of the egg. You should focus on three main observations: look for veins or moving shadows, check air cell growth, and watch for signs of contamination or embryo death. Mark the date and the air cell edge on each egg using a pencil. Keep each candling session under 60–90 seconds for best practices. Handle the egg gently and make sure your hands are clean. These egg candling tips help you protect the developing embryo and get the most accurate results. If you want to know how to candle an egg, remember these tips for candling eggs every time.

Key Takeaways

• Always candle eggs in a dark room using a bright LED light. This helps you see veins, air cell growth, and any signs of contamination.

• Handle eggs gently and keep candling sessions under 60–90 seconds. This protects the developing embryo from temperature and humidity changes.

• Mark the air cell edge with a pencil after each candling session. This allows you to track air cell growth and identify any issues early.

• Look for specific signs at each stage of development, such as veins and movement by Day 7. This helps you assess embryo health and viability.

• Be aware of red flags like blood rings or cloudy spots. Quick action can prevent contamination and protect healthy eggs.

Egg Candling Tools & Setup

LED Candling Light: 200–400+ Lumens

You need a strong, focused light to see inside the egg. A small LED candling light with 200–400 lumens works well for most eggs. White eggs let more light through, so you can use a basic LED. Brown or blue/green eggs need a high-intensity model. Some brands, like Brinsea, offer OvaView and OvaScope candlers. These models block outside light and focus the beam on the egg. This helps you see the air cell and veins more clearly. High-intensity candlers make it easier to spot air cell growth in dark-shelled eggs. The right light lets you check for blood vessels, air cell size, and any signs of contamination or embryo death.

Tip: Use a candler that does not get hot. This keeps the egg safe during candling.

Dark Room or Candling Box

Candling works best in a dark room. Darkness helps you see the inside of the egg much better. Even a powerful flashlight works better when you block out other light. If you cannot darken a whole room, use a candling box. This box blocks outside light and lets you focus the beam on the egg. Always use as little extra light as possible. This makes it easier to spot veins, air cell edges, and any red flags.

Pencil, Record Sheet, Disposable Gloves

You should always handle eggs with clean hands or disposable gloves. This prevents contamination. Use a pencil to mark the date and air cell edge on each egg. Never use a marker, as ink can seep through the shell. Keep a record sheet to track what you see each time you candle. Write down the day, air cell size, and any changes. This helps you follow air cell growth and spot problems early.

Note: Candle eggs in front of the incubator and use a padded towel for safety. This reduces the risk of dropping eggs.

If you want to know how to candle an egg, start with the right tools and setup. This makes candling eggs safer and more effective.

Positioning Eggs: Large End Up, Lighting Angle, Gentle Handling

When you candle eggs, how you hold and position them matters a lot. Always place the egg with the large end facing up. The air cell forms at this end, and you want to check its size and shape each time. This position also helps you spot early signs of embryo movement and air cell growth. If you candle shipped eggs or eggs with a detached air cell, keep them upright and avoid turning them too much. Let them rest for 24–48 hours before the first candling.

Follow these steps for safe and effective candling:

1. Hold the Egg Gently:
   Use your fingertips to support the egg. Avoid squeezing or shaking. Clean hands or disposable gloves help prevent contamination.

2. Large End Up:
   Always point the large end toward the light source. This lets you see the air cell clearly and check for blood vessels or embryo shadows.

3. Lighting Angle:
   Shine the LED candler directly at the large end. Tilt the egg slightly if you need to see veins or the embryo better. For dark or thick shells, use a brighter light and adjust the angle until you spot the key features.

4. Short Sessions:
   Keep each candling session under 60–90 seconds. This protects the embryo from temperature and humidity swings.

Tip: Mark the air cell edge with a pencil after each candling. Track changes on your record sheet. Never use markers, as ink can seep through the shell.

What to look for at each stage:

• Day 4–5: Veins start to appear.

• Day 7: Clear veins and some movement. Air cell should be about 3–4% of the egg.

• Day 14: Large dark area, active embryo, air cell 7–9%.

• Day 18 (Lockdown): Air cell slants, stop turning eggs, raise humidity.

If you see a blood ring, clear egg by Day 10, or a detached air cell, note it on your chart. For more details, check our guide on egg candling day by day and air cell growth chart. Careful positioning and gentle handling help you spot red flags early and support healthy development.

Air Cell Growth Basics in Candling Eggs

Understanding air cell growth is one of the most important parts of candling eggs. The air cell forms at the large end of the egg and grows as moisture leaves the shell during incubation. You need to monitor embryo development by tracking this air sac size at each stage. If you want to know how to candle an egg and get the best results, focus on three main observations: blood vessel activity, air cell size and shape, and any signs of contamination or embryo death.

Target Weight Loss and Air Cell Size (11–13% by Lockdown)

You should aim for a weight loss of about 11–13% by the time you reach lockdown. This target helps the air cell reach the right size for a healthy hatch. If the air sac size is too small or too large, the chick may struggle to hatch or develop properly. Here are some key points:

• The ideal weight loss for fertile eggs by lockdown is about 13% of the original egg weight.

• Poultry and waterfowl eggs should lose between 11% and 13% during incubation.

• Proper air cell growth keeps humidity and moisture levels balanced.

If you see improper air cell growth, you may notice:

• Too much moisture in the egg, leading to weak chicks.

• Too little moisture, causing dehydration or hatching problems.

• Poor hatchability and low chick vitality.

You can use a small scale to weigh each egg at the start and compare it to later weights. This method, along with candling, gives you a clear picture of air cell growth.

Marking Air Cell Edges for Day-by-Day Development Tracking

Marking the air cell edge on each egg helps you track changes over time. After each candling session, use a pencil to draw a line around the air sac size. This simple step lets you see if the air cell is growing at the right pace. Keep a record sheet with the date, air cell size, and your observations. This habit helps you spot red flags early and follow best practices.

Tip: Always keep candling sessions under 60–90 seconds. Handle fertile eggs gently and use only a pencil for marking.

By following these egg candling tips, you can support healthy air cell growth and improve your chances for a successful hatch.

Day-by-Day Development: Candling Chicken Eggs Photo Guide

Candling chicken eggs lets you track embryo growth and spot problems early. You can use this day-by-day development guide to know what to look for at each stage. Always candle in a dark room, use a bright LED, and handle each egg gently. Keep each session under 60–90 seconds. Mark the air cell edge with a pencil after every check. This helps you follow air cell growth and catch red flags before they become serious.

Day 0–3: Clear Egg, Small Air Cell, No Early Judgement

During the first three days, you will not see much change inside the egg. The shell looks clear, and the air cell remains small at the large end. You should check for cracks or marks on the shell before placing the egg in the incubator. Do not expect to see veins or movement yet. Early candling at this stage helps you remove any eggs with obvious shell damage.

Tip: Do not judge embryo viability too early. Some eggs may not show visible changes until Day 4 or 5. Keep all eggs unless you see clear signs of damage or contamination.

If you use advanced tools like Early Embryo Viability Assessment (EEVA), you can sometimes assess embryo potential in the first three days. EEVA software checks how the embryo develops and gives a grade, but most home candlers rely on visual checks.

Day 4–5: Vein Network Appears, Embryo Dot Visible

By Day 4 or 5, you should start to see a network of fine red veins spreading from the center of the egg. A small dark spot, the embryo, may become visible near the veins. This is the first clear sign of life. The air cell remains small, usually about 1–2% of the egg’s volume.

• You should look for:

  • A spider-like pattern of veins.

  • A tiny moving dot (the embryo).

  • No signs of cloudiness or blood rings.

Red Flag: If you see a clear egg with no veins by Day 5, mark it and check again at Day 7. Some embryos develop slowly, especially if the eggs are shipped or stored cold.

You can mark the air cell edge with a pencil. This helps you track air cell growth as incubation continues. If you see a blood ring (a red circle with no movement), this means the embryo stopped developing early. Remove these eggs to prevent contamination.

Day 7: Clear Veins, Embryo Movement, Air Cell 3–4%

At Day 7, candling chicken eggs becomes more rewarding. You should see a strong network of veins and a larger, moving embryo. The air cell now takes up about 3–4% of the egg. Movement inside the egg shows that the embryo is alive and healthy.

• What you should see:

  • Clear, branching veins.

  • The embryo moves when you gently rotate the egg.

  • The air cell is slightly larger than before.

Table: What to Look for at Day 7

Note: Air cell size can vary between eggs. Some may have slightly larger or smaller air cells at this stage. Mark the air cell edge and record your observations. If you see no veins or movement by Day 7, mark the egg for rechecking at Day 10.

Quick Red Flag Checklist for Day 7:

• Clear egg: No veins or movement. Mark and recheck at Day 10.

• Blood ring: Remove the egg safely.

• Cloudy or weepy egg: Possible contamination. Remove and clean your hands.

Photo Caption Example:
Day 7: Healthy embryo with clear veins and active movement. Air cell at 3–4%. Action: Mark air cell edge and record activity.

Alt Text Example:
Candling chicken egg at Day 7 showing strong veins, moving embryo, and visible air cell.

Candling chicken eggs at these early stages helps you spot healthy development and catch problems before they affect the whole batch. Always handle eggs gently, use a pencil for marking, and keep your records up to date. This careful approach supports healthy hatching and gives you confidence as you follow the day-by-day development of your eggs.

Day 10: Dense Veins, Expanding Shadow, Air Cell 5–6%

On Day 10, candling gives you a clear view of the developing embryo. You see dense veins spreading across the inside of the egg. The embryo casts a larger shadow, showing strong activity. The air cell now reaches about 5–6% of the egg’s volume. You should check for three main things: active blood vessels, proper air cell growth, and any signs of contamination or embryo death.

When you candle the egg, hold it with clean hands and keep the large end up. Use a bright LED to shine light into the air cell. Look for these signs:

• Dense, branching veins

• Expanding dark shadow from the embryo

• Air cell edge marked from previous candling sessions

If you see a clear egg with no veins or movement by Day 10, this often means the egg is infertile or the embryo stopped developing early. You can remove these eggs or mark them for rechecking in 2–3 days. Watch for blood rings, which look like a red circle inside the egg. This is a sign of early embryo death. Remove eggs with blood rings to prevent contamination.

Tip: Keep each candling session under 60–90 seconds. Mark the air cell edge with a pencil, not a marker.

Day 10 Candling Table

Photo Caption:
Day 10: Dense veins and expanding embryo shadow. Air cell at 5–6%. Action: Mark air cell edge and record activity.

Alt Text:
Candling chicken egg at Day 10 showing dense veins, large shadow, and air cell.

Day 14: Large Dark Area, Active Embryo, Air Cell 7–9%

By Day 14, candling reveals a large dark area inside the egg. The embryo grows quickly and moves more often. You see fewer veins because the chick fills most of the space. The air cell now takes up about 7–9% of the egg’s volume. You should focus on three things: embryo movement, air cell size, and any red flags.

When you candle the egg, look for these signs:

• Large dark area with active movement

• Air cell edge clearly marked

• Veins may fade as the chick grows

If you see a cloudy or weepy egg, this may mean contamination. Remove these eggs to keep the rest safe. Detached air cells are common in shipped eggs. Keep these eggs upright and avoid turning them too much. Mark the air cell edge and record your observations.

Note: Handle each egg gently. Use a pencil to mark the air cell. Avoid long candling sessions.

Day 14 Candling Table

Photo Caption:
Day 14: Large dark area and active embryo. Air cell at 7–9%. Action: Mark air cell edge and check for movement.

Alt Text:
Candling chicken egg at Day 14 showing large dark area, active embryo, and air cell.

Day 18 (Lockdown): Slanted Air Cell, Stop Turning, Raise Humidity

On Day 18, you reach the lockdown stage. Candling shows a slanted air cell at the large end of the egg. The chick gets ready to hatch and moves into position. You should stop turning the eggs and raise humidity in the incubator. This helps the chick break through the shell and hatch safely.

During lockdown candling, look for these signs:

• Slanted air cell at the large end

• Chick’s head near the air cell

• Internal pip (small crack inside the egg)

If you see a malpositioned chick, watch closely but avoid frequent candling. Eggs with detached air cells need extra care. Keep them upright and limit handling. Do not open the incubator often during hatch. This keeps humidity stable and protects the chicks.

Alert: Only candle quickly at lockdown to confirm internal pip and chick position. Avoid long sessions to prevent membrane drying.

Day 18 Lockdown Candling Table

Photo Caption:
Day 18: Slanted air cell and chick ready to hatch. Action: Stop turning, raise humidity, and minimize handling.

Alt Text:
Candling chicken egg at Day 18 showing slanted air cell and chick in hatching position.

Day 19–21: Internal Pip, Air Cell Movement, Hatching Signs

You have reached the final days of incubation. This is when the most exciting changes happen inside each egg. The chick prepares to hatch, and you can spot important signs if you candle carefully.

What should you look for during Day 19–21?

• Internal pip: The chick breaks through the inner membrane into the air cell. You may see a small shadow or movement near the air cell edge.

• Air cell movement: The air cell may wobble or shift as the chick breathes and moves. This is a good sign that the chick is alive and getting ready to hatch.

• Hatching signs: You might hear faint peeping or see the shell start to crack from the inside.

Tip: Candle quickly and only if needed. At this stage, you want to keep the incubator closed as much as possible to hold in humidity and warmth.

Table: What to Look for on Day 19–21

Red Flag Quick-Check Table

Alert: If you see a chick pip away from the air cell, watch closely. Some chicks can still hatch, but you should avoid opening the incubator unless absolutely necessary.

Photo Caption Example:
Day 20: Chick has internally pipped into the air cell. You can see movement and hear faint peeping. Action: Keep humidity high and avoid opening the incubator.

Alt Text Example:
Candling egg at Day 20 showing internal pip and chick movement near the air cell.

Key Reminders for Day 19–21:

• Candle only if you need to confirm internal pip or check for movement.

• Keep each session under 60–90 seconds.

• Handle each egg gently and always use clean hands.

• Do not help chicks hatch unless you see clear signs of distress and have experience.

You can find more details about lockdown candling and hatching checks in our egg candling day by day guide.

Other Species: Adjust Timeline by Incubation Percentage

Not all eggs develop at the same speed. If you incubate duck, quail, or other bird eggs, you need to adjust your candling timeline. Use the percentage of the total incubation period to match the right candling days.

How to adjust your candling schedule:

1. Find out the total incubation days for your species.

2. Divide the process into key stages using percentages.

3. Candle at similar development points as you would for chicken eggs.

Example Table: Adjusting Candling for Other Species

Tip: For small or porous eggs, use extra darkness and a high-brightness candler. Candle less often to avoid stress.

Photo Caption Example:
Day 14 (quail): Large dark area, active embryo, air cell at 7–9%. Action: Mark air cell edge and check for movement.

Alt Text Example:
Candling quail egg at Day 14 showing active embryo and air cell growth.

Key Points for Other Species:

• Always track air cell growth and embryo movement.

• Mark the air cell edge with a pencil after each candling.

• Watch for red flags like blood rings, clear eggs, or detached air cells.

• Rest shipped eggs upright and reduce handling.

You can find more species-specific candling timelines and air cell growth charts in our resources section.

Red Flags in Egg Candling & What to Do

When you practice egg candling, you want to spot potential issues early. Recognizing red flags helps you protect viable eggs and avoid contamination. You should always focus on three main things: blood vessel activity, air cell size and shape, and any signs of contamination or embryo death. If you see something unusual while candling eggs, use this troubleshooting for candling eggs guide to decide what to do next.

Here is a quick table of common red flags and what they mean for checking egg viability:

You should always keep candling sessions under 60–90 seconds. Handle each egg gently and mark the air cell edge with a pencil, not a marker. If you see any of these warning signs, act quickly to protect the rest of your batch.

Blood Rings

A blood ring is one of the most important red flags you can find during candling. You will see a thin, red circle inside the egg, usually not moving. This ring forms when the embryo dies early, and the blood vessels collapse. Blood rings often appear between Day 4 and Day 10, but you can spot them at any stage.

What to look for:

• A clear, unbroken red ring inside the egg.

• No visible embryo movement.

• No active blood vessels.

When you see a blood ring, you should remove the egg from the incubator. Keeping non-viable eggs can lead to contamination and risk the health of your viable eggs. Discarding eggs with blood rings is a key step in troubleshooting for candling eggs.

Tip: Always wash your hands after handling eggs with blood rings. Mark the egg and record the removal on your chart.

Photo Caption:
Day 7: Blood ring visible, no embryo movement. Action: Remove egg to prevent contamination.

Alt Text:
Candling egg at Day 7 showing a clear blood ring and no active embryo.

Cloudy or Floating Spots

Cloudy or floating spots inside the egg can signal contamination or shell problems. You may notice these spots as gray, white, or dark patches that do not move. Sometimes, you will see mottled eggshells with translucent spots. These spots often mean the eggshell structure is disorganized, which can cause abnormal moisture and air loss.

What to look for:

• Cloudy areas or floating spots that do not match normal embryo growth.

• Mottled or patchy shell appearance.

• No clear blood vessels or embryo movement.

Cloudy eggs often have lower hatchability. Stress or disease in hens can cause these shell problems. The more severe the mottling, the more likely you will see weight loss and poor air cell growth. If you find cloudy or floating spots, you should remove the egg to protect the rest of your batch.

Note: Mark the air cell edge and record any unusual spots. If you see rapid weight loss or shrinking air cell, check your humidity and incubation settings.

Photo Caption:
Day 10: Cloudy spot visible, no clear veins. Action: Remove egg and check for contamination.

Alt Text:
Candling egg at Day 10 showing cloudy area and no visible embryo.

Leaking or Bad Odor

Leaking eggs or those with a bad odor are serious red flags. You may notice liquid seeping from the shell or a strong, unpleasant smell. These signs mean the egg is contaminated, often by bacteria. If you leave these eggs in the incubator, they can spread germs to other eggs and lower your hatch rate.

What to look for:

• Wet spots or liquid leaking from the shell.

• Strong, rotten, or sour smell.

• Discoloration or unusual color on the shell.

You should discard any egg that leaks or smells bad right away. Always remove broken, leaking, or dirty eggs to prevent contamination. Handle these eggs with gloves if possible and clean your hands after touching them.

Alert: Never try to save a leaking or smelly egg. Removing it quickly is the best way to protect your viable eggs.

Photo Caption:
Day 14: Egg leaking fluid, strong odor present. Action: Discard egg immediately.

Alt Text:
Candling egg at Day 14 showing leaking fluid and signs of contamination.

When you candle eggs, always watch for these red flags. Quick action keeps your incubator safe and supports healthy development. If you want more tips on what to look for or need help with troubleshooting, check our guides on egg candling day by day and air cell growth chart. Careful checking egg viability at each stage helps you spot non-viable eggs and focus on the ones with the best chance to hatch.

No Veins or Development

When you candle eggs, you want to see clear signs of life. One of the most important things to check is the presence of veins. If you do not see any veins or development by Day 7, you should mark the egg and check again at Day 10. Sometimes, embryos develop slowly, especially in shipped eggs or those stored for a long time. However, if the egg still looks clear at Day 10, it is likely infertile or the embryo stopped developing early.

What to look for:

• No visible blood vessels or spider-like veins

• No dark embryo shadow or movement

• Only the yolk shadow and a small air cell at the large end

Tip: Always candle in a dark room and use a bright LED. Hold the egg with the large end up. Keep each session under 60–90 seconds to protect the embryo.

You can use this table to help decide what to do if you see no veins or development:

If you find non-viable eggs, remove them from the incubator. This helps prevent contamination and protects the rest of your batch. Always wash your hands after handling these eggs.

Photo Caption:
Day 10: No veins or embryo visible. Action: Remove egg as non-viable.

Alt Text:
Candling egg at Day 10 showing clear interior with no veins or embryo.

Detached or Cracked Air Cell

Air cell abnormalities can cause problems during incubation. A detached air cell means the air pocket at the large end of the egg has separated from the shell membrane. This often happens with shipped eggs or eggs that have been shaken. You may notice the air cell moves or appears misshapen when you tilt the egg during candling.

What to look for:

• Air cell shifts or floats when you gently rotate the egg

• Irregular or jagged air cell edge

• Cracks in the shell near the air cell

If you see a detached air cell, you should rest the egg upright (large end up) for 24–48 hours before starting incubation. This helps the air cell settle back into place. During incubation, handle these eggs very gently and avoid turning them too often. For cracked air cells, you may see a line or break in the shell. These eggs have a higher risk of contamination and moisture loss.

Quick Action Steps for Detached or Cracked Air Cell:

1. Stand the egg upright in the incubator.

2. Reduce turning frequency, especially in the first week.

3. Candle only at the large end and keep sessions short.

4. Mark the air cell edge with a pencil after each candling.

Alert: Detached air cell shipped eggs need extra care. Avoid shaking or rolling them. If you see leaking or a bad odor, remove the egg right away.

Photo Caption:
Day 7: Detached air cell visible, air pocket shifts when egg is tilted. Action: Rest upright and reduce handling.

Alt Text:
Candling egg at Day 7 showing detached air cell with irregular edge.

If you track air cell growth and spot these issues early, you can give viable eggs the best chance to develop. Always record your findings and follow best practices for candling eggs.

Candling Chicken Eggs: Photo Captions & Alt Text

Captioning: Day, Visible Structures, Recommended Action

When you take photos during candling, clear captions and alt text help you and others learn from each stage. Good captions do more than repeat what you see. They add context, highlight key features, and suggest what you should do next. Use present tense and keep your tone friendly, as if you are explaining the process to a friend. This approach makes your egg candling day by day records more useful and accessible.

Best practices for captioning candling photos:

• Give the day of incubation.

• Point out visible structures, such as veins, air cell, or embryo movement signs.

• Suggest the recommended action, like marking the air cell or removing a non-viable egg.

• Add new information or context, not just what is obvious in the image.

• Use present tense for immediacy.

Tip: Always keep your hands clean, handle eggs gently, and use a pencil to mark the shell. Limit each session to 60–90 seconds.

Here is a table to help you write captions and alt text for each key stage and red flag:

Note: For detached air cell shipped eggs, always rest them upright for 24–48 hours and candle only at the large end.

You can use these examples to build your own air cell growth chart or troubleshooting guide. Accurate captions and alt text make your candling records more valuable for learning and sharing.

Handling Shipped or Porous Eggs During Candling

Resting Upright, Fewer Candling Sessions

Shipped eggs often arrive with detached air cells or small cracks. You should always rest these eggs upright, with the large end up, for 24–48 hours before starting incubation. This helps the air cell settle back into place. If you see the air cell moving or floating during candling, keep the egg upright and avoid turning it too much.

You need to reduce the number of candling sessions for shipped or fragile eggs. Each time you handle an egg, you risk shaking the air cell or damaging the embryo. Try to candle only at key points, such as Day 4–5, Day 7, Day 14, and Day 18 (lockdown). Keep each session under 60–90 seconds. Always use clean hands and handle eggs gently. Mark the air cell edge with a pencil after each check.

Tip: For detached air cell shipped eggs, candle only at the large end and avoid rolling the egg.

Table: Key Steps for Shipped Eggs

Extra Darkness for Porous or Small Eggs

Porous eggs and small eggs, like quail eggs, let more light through the shell. You need extra darkness in your candling area to see details clearly. Turn off all lights and close curtains. Use a high-brightness LED candler for best results. For small eggs, lower the exposure on your camera if you take photos.

When you candle porous eggs, focus on three things: blood vessel activity, air cell size and shape, and signs of contamination or embryo death. If you see a clear egg by Day 10, mark it and check again in 2–3 days. Watch for blood rings or cloudy spots, which are red flags.

Note: Candle porous or small eggs less often. Too much handling can cause damage or stress.

You can find more tips in our egg candling day by day guide and air cell growth chart.

Lockdown & Hatching Checks in Candling Eggs

Quick Final Candling, Internal Pip Confirmation

As you reach Day 18, you enter the lockdown phase. This is a critical time for your eggs. You want to do a quick final candling to check for internal pip and confirm the chick’s position. Focus on three things: blood vessel activity, air cell size and shape, and any signs of contamination or embryo death. Keep your session under 60–90 seconds. Always handle eggs with clean hands and use a pencil to mark the air cell edge if needed.

Follow these key steps during lockdown and hatching checks:

1. Candle the eggs one last time to confirm internal pip and chick position.

2. Stop turning the eggs. Chicks need to settle for hatching.

3. Increase the humidity in your incubator. This helps prevent the membrane from drying out.

4. Chick-proof any water sources to keep new chicks safe.

5. Close the lid and avoid opening the incubator.

You should see a slanted air cell, the chick’s head near the air cell, and sometimes movement or peeping. The air cell should reach about 11–13% of the egg’s volume by lockdown. If you spot a malpositioned chick or a detached air cell, note it and observe closely. For detached air cell shipped eggs, keep them upright and minimize handling.

Tip: Only candle at lockdown if you need to confirm internal pip or chick position.

Minimize Opening Incubator During Hatch

During hatching, you want to keep the incubator closed as much as possible. Each time you open the lid, you lose humidity and heat. This can cause the membrane to dry out and make hatching harder for chicks. Watch for embryo movement signs and listen for peeping through the shell.

• Keep the incubator closed after lockdown.

• Only open if you must remove a leaking or bad egg.

• Observe through the window or use a camera if possible.

If you see a blood ring, clear egg, or leaking egg, remove it quickly and safely. For malpositioned chicks, observe but avoid frequent intervention. Careful monitoring and minimal disturbance help your chicks hatch safely.

Note: For more details on egg candling day by day, air cell growth chart, and red flag candling, visit our related guides.

FAQ: Egg Candling & Day-by-Day Development

What if I can't see inside the egg?

Sometimes, you may find it hard to see inside an egg, especially if the shell is dark or thick. Try these steps:

• Use a high-brightness LED candler.

• Candle in a completely dark room or use a candling box.

• Hold the egg with the large end up and shine the light at the air cell.

• For small eggs, lower your camera exposure if you take photos.

If you still cannot see veins or embryo movement signs by Day 7, mark the egg and check again at Day 10. Some eggs, like those from shipped batches, may develop slowly. If the egg remains clear at Day 10, it likely did not develop. Remove it to protect the rest.

Tip: For detached air cell shipped eggs, rest them upright for 24–48 hours before candling. Candle only at the large end to avoid disturbing the air cell.

How often should I candle eggs?

You do not need to candle eggs every day. Focus on key time points for the best results:

Keep each session under 60–90 seconds. Always use clean hands and handle eggs gently. Mark the air cell edge with a pencil after each check.

Is it safe to candle eggs during the day?

You can candle eggs during the day, but you must block out all outside light. Choose a windowless room or wait until evening. Use a candling box if you cannot darken the room. This helps you see blood vessel activity, air cell size, and any signs of contamination or embryo death. Never candle eggs in direct sunlight, as this can heat the egg and harm the embryo.

Note: Always keep the three main observations in mind: blood vessel activity, air cell growth, and red flags like blood rings or cloudy spots. For more tips, visit our egg candling day by day guide or check the air cell growth chart.

What should I do if an egg smells bad or leaks?

If you notice an egg with a strong odor or see liquid leaking from the shell, you need to act quickly. These signs often mean the egg has a bacterial infection. A leaking or smelly egg can spread germs to other eggs in your incubator.

Steps to follow:

1. Put on disposable gloves before touching the egg.

2. Remove the egg from the incubator right away.

3. Place the egg in a sealed bag before throwing it away.

4. Wash your hands and clean any surfaces the egg touched.

Alert: Never try to save a leaking or smelly egg. Removing it protects the rest of your batch.

You should check for these red flags during each candling session. If you see a weepy egg or smell something bad, stop candling and remove the egg. This keeps your other eggs safe and healthy.

How do I handle eggs with detached air cells?

Detached air cells happen most often in shipped eggs. You might see the air cell move or float when you tilt the egg during candling. This can lower hatch rates, but you can still give these eggs a chance.

What to do:

• Stand the egg upright with the large end up for 24–48 hours before starting incubation.

• Reduce turning, especially in the first week.

• Candle only at the large end and keep sessions short (under 60–90 seconds).

• Mark the air cell edge with a pencil after each check.

Tip: Detached air cell shipped eggs need extra care. Avoid shaking or rolling them.

Can I candle eggs from different species the same way?

You can use the same basic candling method for most bird eggs, but you need to adjust your timing. Different species have different incubation periods. For example, chicken eggs take 21 days, while duck eggs take about 28 days.

How to adjust your candling schedule:

You should always track three things: blood vessel activity, air cell size and shape, and signs of contamination or embryo death. For small or porous eggs, use extra darkness and a bright light. Candle less often to avoid stress.

Note: For more details, check the egg candling day by day guide and air cell growth chart on our site.

What if the air cell looks too small or too large?

When you candle your eggs, you might notice the air cell is not the right size. A small air cell means the egg is losing too little moisture. A large air cell means the egg is losing too much. Both can affect the chick’s ability to hatch.

What you should do:

• If the air cell is too small:
  Lower the humidity in your incubator. This helps the egg lose more moisture. Check again at the next key time point, like Day 10 or Day 14.

• If the air cell is too large:
  Raise the humidity. This slows down moisture loss. Mark the air cell edge with a pencil after each candling session.

Tip: The air cell should reach about 3–4% by Day 7, 7–9% by Day 14, and 11–13% by lockdown. Use a small scale to track weight loss for extra accuracy.

Always focus on blood vessel activity, air cell size and shape, and any signs of contamination or embryo death.

What if the shell is too dark to see through?

Some eggs have dark or speckled shells, making it hard to see inside. You can still check for embryo movement signs and air cell growth with the right setup.

Try these steps:

• Use a high-brightness LED candler.

• Candle in a completely dark room or use a candling box.

• Hold the egg with the large end up and shine the light at the air cell.

• For small eggs, lower your camera exposure if you take photos.

Note: If you still cannot see veins or movement by Day 10, mark the egg and check again in 2–3 days. Some eggs, especially shipped ones, may develop slowly.

If you cannot see inside at all, focus on other clues like weight loss or shell temperature. Always handle eggs gently and keep sessions short.

How do I avoid harming the embryo during candling?

You want to protect the embryo every time you candle. Follow these steps to keep your eggs safe:

1. Wash your hands or wear disposable gloves before touching eggs.

2. Handle each egg gently. Avoid shaking or squeezing.

3. Keep each candling session under 60–90 seconds.

4. Always use a pencil to mark the air cell edge. Never use a marker.

5. Candle at the large end and avoid rolling the egg, especially for detached air cell shipped eggs.

Alert: For shipped eggs or those with a detached air cell, rest them upright for 24–48 hours before candling. Reduce turning and only candle at key time points.

Focus on three things during candling: blood vessel activity, air cell size and shape, and signs of contamination or embryo death. Careful handling and short sessions help you avoid harming the embryo and support healthy development.

When should I stop candling before hatch?

You want to know the best time to stop candling before your chicks hatch. Most people do their final check at Day 18, right before lockdown. After this point, you should avoid opening the incubator unless you see a serious problem. This helps keep humidity and temperature steady, which is important for healthy chicks.

During your last candling session, focus on three things:

• Blood vessel activity: Look for signs that the chick is still alive.

• Air cell size and shape: The air cell should reach about 11–13% of the egg’s volume by Day 18.

• Signs of contamination or embryo death: Watch for blood rings, cloudy spots, or bad odors.

After Day 18, you should only candle if you need to confirm an internal pip or check for embryo movement signs. Too much handling can cause the membrane to dry out or stress the chick. For detached air cell shipped eggs, keep them upright and candle only at the large end if you must check.

Tip: Keep each session under 60–90 seconds. Always use clean hands and a pencil for marking.

Here is a quick table to help you decide:

If you see a red flag, such as a blood ring or leaking egg, remove it quickly and safely. Otherwise, keep the incubator closed and let the chicks hatch in peace.

For more tips on egg candling day by day or how to use an air cell growth chart, check our related guides.

Keep Learning: Egg Candling & Incubation Resources

Candling Fertile Eggs Timeline

You can improve your skills by following a clear timeline for candling. Most people check eggs at Day 4–5, Day 7, Day 10, Day 14, and Day 18. At each point, you should look for three things: blood vessel activity, air cell size and shape, and any signs of contamination or embryo death. Use a pencil to mark the air cell edge after each session. Keep each check under 60–90 seconds and handle eggs gently.

Here are some helpful resources for learning more:

• Guide to Incubation

• Egg Candling! Tips, Tricks, and Best Practices.

• How to Tell a Fertile vs INfertile Egg (Pictures)

Tip: Keep a record sheet for each egg. This helps you spot trends and troubleshoot issues.

Humidity & Weight-Loss Method

You need to control humidity to help the air cell grow at the right rate. Aim for about 11–13% weight loss by lockdown. Weigh each egg at the start and at key points. Compare the weight to your air cell growth chart. If the air cell is too small, lower humidity. If it is too large, raise humidity.

You can find more details in these guides:

• Humidity discussion

• A Guide to Humidity, Weighing and Lockdown

• Testing/calibrating incubator thermometers and hygrometers

High Altitude Incubation

If you live at high altitude, you may need to adjust your incubation process. Lower air pressure can cause eggs to lose moisture faster. You should monitor air cell growth closely and check weight loss more often. Sometimes, you need to raise humidity to keep the air cell from growing too quickly.

Note: Always use a bright light for candling at high altitude. Dark shells or small eggs may need extra darkness for best results.

You can find more tips and troubleshooting steps in our egg candling day by day and air cell growth chart articles.

Species-Specific Timelines

Every bird species has its own incubation timeline. You need to adjust your candling schedule based on the total days for each type of egg. This helps you track blood vessel activity, air cell growth, and spot red flags like blood rings or detached air cells at the right time.

Here is a table to guide you through the main milestones for common poultry and game birds:

At each key point, you should look for three things:

• Blood vessel activity: Veins appear and grow stronger.

• Air cell size and shape: Mark the edge with a pencil after each check.

• Signs of contamination or embryo death: Watch for blood rings, clear eggs, or weepy shells.

Tip: For shipped eggs or those with a detached air cell, rest them upright for 24–48 hours. Candle only at the large end and reduce turning.

Red Flag Quick-Check Table

Photo Caption Example:
Day 7 (duck): Clear veins and small air cell. Mark air cell edge and record activity.

Alt Text Example:
Candling duck egg at Day 7 showing visible veins and air cell.

You can find more details for each species in our egg candling day by day and air cell growth chart guides.

You play a key role in the hatching process. Regular egg candling helps you track chick development and spot red flags. You should candle eggs at important days, like Day 4–5, Day 7, Day 10, Day 14, and Day 18. Each time, check blood vessel activity, air cell growth, and signs of contamination or chick death. Mark the air cell edge with a pencil and keep sessions short. These tips help you support chick health and improve hatching success. Stay observant during the hatching process. Use this guide to boost your hatching results and give every chick the best chance for a successful hatch. Wishing you hatching success and many healthy chick arrivals!

Remember: Careful candling eggs and tracking each chick’s progress leads to better hatching process outcomes and more chick success.

FAQ

What should you look for during egg candling?

You should check three things: blood vessel activity, air cell size and shape, and any signs of contamination or embryo death. These help you track development and spot problems early. Always candle in a dark room and keep each session under 60–90 seconds.

How do you handle eggs with a detached air cell?

Stand the egg upright with the large end up for 24–48 hours. Reduce turning, especially for shipped eggs. Candle only at the large end to check air cell growth. Handle gently and mark the air cell edge with a pencil after each check.

What does a blood ring mean?

A blood ring shows early embryo death. You will see a red circle inside the egg that does not move. Mark the egg and remove it from the incubator. This helps prevent contamination and protects the rest of your eggs.

When should you remove a clear egg?

If you see a clear egg with no veins by Day 10, it likely means the egg is infertile or the embryo stopped early. Mark it and recheck in 2–3 days. If still clear, remove it to keep your batch healthy.

How can you tell if the air cell is growing correctly?

Compare the air cell to the target size: about 3–4% by Day 7, 7–9% by Day 14, and 11–13% by lockdown. Mark the air cell edge each time. Use a small scale for extra accuracy if you want to track weight loss.