Candling Eggs: How to Candle an Egg (A Complete Guide)

Candling a batch of eggs

Egg candling is an age-old technique that allows poultry enthusiasts and farmers to assess the development and viability of embryos inside chicken eggs. 

Using a light source, one can view the interior and distinguish between developing chicks and non-viable or dead egg candling situations. 

This guide delves into the intricacies of candling chicken eggs, involving the best practices, insights on what to look for, and determining when to candle chicken eggs.

Embark on a journey of understanding the magical world of eggs, from the earliest stages of development to before they’re ready to hatch.

What Is Egg Candling?

The process of candling eggs

Egg candling is a simple but crucial technique used to examine the development and viability of eggs during the incubation process. By shining a bright light source like a flashlight or an egg candler through the egg, you can see inside the egg to determine whether it’s fertile and how well the developing eggs are progressing. 

This non-invasive method provides valuable information, especially if you’re hoping to hatch baby chicks. Traditionally, candling was done with a candle, but today’s technology offers specialized devices.

Knowing when to perform this is essential, as it helps assess whether the eggs are viable or not. Incubating eggs that are not viable can introduce the risk of bacteria that can harm the baby chicks in adjacent, healthy eggs.

Overall, egg candling is a critical practice for anyone involved in breeding poultry or simply trying to hatch baby chicks. It serves as an “egg-ray,” giving you a glimpse into the egg’s development stage. 

However, caution should be exercised while handling the eggs to prevent any damage.

Why Candle an Egg?

Candling an egg allows poultry keepers and hobbyists to peek inside the egg without breaking it. This technique is vital for determining if an egg is fertile or not and for spotting any irregularities.

The process of candling provides a wealth of information about the developing embryo inside the egg. 

You’ll be able to see the size of the air cell and track its changes, which helps in understanding the hydration levels in the egg. 

Moreover, it shows the yolk position and reveals whether the fertilized egg is developing as it should.

One main reason you need to candle eggs is to identify which eggs are viable and which are not. Bad eggs, also known as “yolkers” or “quitters,” can turn rotten and contaminate other eggs in the incubator.

Candling allows you to discard eggs that show no signs of development or that have ceased to develop, thus maintaining a healthy environment for the rest.

Candling also offers an opportunity to examine eggs before incubation. This preliminary check is good for removing eggs with obvious flaws like thin shells or irregular shapes, thereby increasing the success rate of hatching. 

After all, incubating unhealthy eggs is a waste of time and resources. By weeding out the bad and rotten eggs, you’re optimizing the hatching process for the best results.

Equipment Needed for Candling Eggs

Equipment for candling eggs

If you plan on candling eggs, having the right equipment ensures a smooth and efficient process. With the right tools, you can determine whether you have fertile eggs or unfertilized eggs on your hands.

Here’s a breakdown of what you’ll need for successfully candling eggs:

  • Light source: The most crucial part of the candling process is the light source. A specialized egg candler is often preferred, but a strong flashlight or even your mobile phone can also do the trick.
  • Dark room: To properly look inside the interior of an egg, it’s best to carry out candling in a dark room. This enhances the visibility of what’s inside the egg.
  • Soft surface: While candling is done, you’ll want a soft surface like a towel or cushion where you can safely place the eggs from the incubator. This minimizes the risk of breaking or damaging the eggs.
  • Tweezers and sanitizer: Occasionally, you might notice foreign materials on the eggshell. Tweezers can help remove them, and sanitizer ensures everything remains hygienic.
  • Observation chart or notebook: Keeping track of what you see in each egg allows you to make informed decisions later. Note down observations like air cell size and any signs of development.
  • Gloves: Wearing gloves can minimize the transfer of oils or bacteria to the egg’s surface. It’s a simple but effective hygiene measure.
  • Timer or stopwatch: Keeping track of time ensures that eggs aren’t exposed to light for too long, which could affect the incubation process.

Having these types of equipment handy will streamline your candling experience and increase your chances of hatching healthy chicks.

How to Candle an Egg

An egg during candling

Candling an egg is an essential skill for anyone interested in raising poultry or hatching birds from eggs. This non-invasive technique allows you to peek inside the egg to assess its viability and monitor the developing embryo. 

From preparing the candling area to returning the eggs safely to the incubator, each step is crucial for a successful candling experience.

Step 1: Preparing the candling area

Before you start, prepare a dark room to enhance visibility within the egg. Gather all your equipment, including a light source, soft towel, gloves, and a notebook for observations. 

The less you handle the eggs during this process, the better, so make sure everything is within reach.

Step 2: Removing the eggs from the incubator

Turn off the incubator’s turning mechanism if it has one. Carefully take your eggs out and set them on a soft surface. Handle the eggs gently to avoid causing any damage to the developing embryos.

Step 3: Positioning the light source

Choose a strong light source, like an egg candler or a powerful flashlight. Position the light so that it shines upwards. You’ll be placing the larger end of the egg against this light to look within the egg.

Step 4: Holding the egg for candling

Wear gloves to minimize contamination. Hold the egg with the larger end facing downwards and gently place it against the light source. Turn the egg slightly to get different views and better insights into its development.

Step 5: Observing and taking notes

Look for signs of development like veining, the size of the air cell, or a growing embryo. Use your notebook to jot down what you see. 

This will help you track progress and make decisions on whether to keep or remove certain eggs.

Step 6: Returning the eggs to the incubator

Once you’re done observing, carefully put the eggs back into the incubator. Make sure to resume the turning function if your incubator has one. 

Remember, the less you handle the eggs, especially when returning them, the better for their development.

The video below shows the step-by-step procedure of egg candling:

Why And How To Candle Your Eggs

What to Look for When Candling Eggs

Embryo visible during egg candling

Candling eggs is more than just shining a light through them—it’s a methodical process that requires keen observation. 

Knowing what to look for can make the difference between a successful hatch and disappointment. To ensure you’re on the right track, it’s essential to focus on a few indicators, from the air sac to the embryo itself.

1. Air sac

The air sac is a crucial part of an egg’s development and is often located at the larger end of the egg.

Over time, it should grow bigger as the contents of the eggs change and the embryo develops. A small or non-existent air sac could be a sign that the egg is not viable.

2. Pores in the eggshell

An eggshell has tiny pores that allow the embryo to breathe. While candling, you may not see the pores directly, but a shell that looks too thick or cloudy might indicate poor quality.

Clear eggs often signify good shell quality and better chances for embryo survival.

3. Yolk

The yolk is the nutrient source for the developing embryo. In a viable egg, you might not always see the yolk clearly, especially in dark-colored eggs. 

But a clear separation between the yolk and the egg white is generally a good sign during early stages, like eggs on day 7.

4. Blood vessels and a red ring around the yolk

Seeing a network of blood vessels or a web of blood vessels around the yolk is a positive indicator of a growing embryo. 

However, a red ring around the yolk, also known as a blood ring, is a sign of a terminated development and means the egg should be discarded.

5. The embryo itself

In the later stages of incubation, you may be able to see the embryo. Eggs with a dark mass and noticeable movement are usually healthy. 

Every egg develops at its own rate, but seeing a growing, active embryo is usually a sign of a healthy egg.

Understanding the intricate details of what to look for when candling eggs is vital for anyone interested in incubating and hatching. 

Armed with this knowledge, you’re well-prepared to make informed decisions about which eggs to keep and which to discard, maximizing your hatching success.

When to Candle Your Eggs

Candling pictures until day 21
Image credit: Nicole Duncan / Pinterest

Knowing when to candle your eggs is crucial for a successful hatch. It’s typically done at three key periods: early in the first week of incubation, around the second week, and it’s best to avoid it near the end of the cycle.

1. First Candling: Around Day 7 to 10

It’s a good idea to candle eggs around day 7 to day 10 of incubation. During this period, you can easily determine if the eggs are developing as they should be. 

Candling early is crucial for identifying any issues that may prevent the eggs from hatching. You should be able to see some initial signs of development, like blood vessels.

2. Second Candling: Around Day 14 to 18

The best time to plan for a second candling is around day 14 to day 18. By this time, the embryo has grown considerably. 

If you’ve been incubating your eggs for two weeks, this is when it’s easier to detect which eggs are viable. However, it can also be difficult to candle darker-colored eggs because the developing embryo blocks more light.

3. Third Candling: Why It’s Best to Avoid After Day 18

Candling after day 18 is generally discouraged. Eggs are nearing the end of their 21-day incubation cycle, and handling them too much could be harmful.

The number of times you candle should be minimized to ensure that the eggs are not disturbed during critical periods of development.

Over the years, I’ve had my fair share of experiences with candling chicken eggs. I remember the first time I set the eggs inside the incubator, excited but unsure what to expect. 

By day 7, I knew it was the best time to candle, and as I shined the light into the egg, my heart swelled, seeing the network of veins—a sign of a developing embryo. 

However, not all was smooth sailing. Once, I made the mistake of candling after day 18 and disrupted the hatching process, which taught me the importance of timing. 

Believe me, when it comes to hatching eggs, it’s a good idea to candle, but knowing when and how is crucial for success.

For more tips on when to candle chicken eggs, watch this informative video below:

When to Candle Chicken Eggs | What is a Red Ring?

Egg Candling Tips and Best Practices

When it comes to successfully raising chickens, knowing how to candle eggs effectively is a game-changer. This process gives you an insider’s view of what’s happening within the shell. 

However, to get the most accurate insights, there are some essential tips and best practices you should know:

  • Use a dark room: For the best results, try to candle eggs in a dark room. This makes it easier to see what’s going on inside the egg. Proper lighting will give you a clearer view of the developmental stages.
  • Limit handling: Eggs can also be sensitive to temperature and handling. The less you handle them, the better the hatching success rate will be. Take them out of the incubator to candle only when necessary.
  • Candling device: Use a flashlight or specialized candling device that has LED technology. These types of light sources give a sharper focus and are safe for the eggs, helping you see when candling.
  • Look for red flags: Eggs that never show any signs of development or have a bad smell could be rotten. Remove them immediately, as they can risk the health of other eggs.
  • Know your egg types: Different breeds produce different types of egg shells, which can affect what you see when candling. For instance, brown eggs may be harder to see through compared to white eggs.
  • Time management: Schedule your candling process so that you are not disrupting the incubation period. Time out of the incubator should be minimal to ensure the eggs go on to hatch chicks successfully.
  • Seek expert advice for doubts: If you are uncertain about what you are seeing or about eggs that could be problematic, consult someone with experience. Getting a second opinion can often avoid mistakes.
  • Record observations: Always jot down what you observe. This can help you identify trends or issues that might arise later in the incubation process.

Hopefully, these tips have offered you some valuable insights to improve your egg-candling skills. Remember, practice makes perfect, so keep candling and keep learning!

Frequently Asked Questions

Eggs being arranged for candling

Should You Candle Eggs a Hen Is Sitting On?

Candling eggs a hen is sitting on is usually unnecessary. Mother hens know what they’re doing, and they will take care of the chicken’s eggs. That said, if you’re super curious or have a concern, you can candle them. 

Just remember that each time you disturb a sitting hen, you risk her abandoning her eggs. If you absolutely must check, be as quick and gentle as possible.

What Does a Candled Egg Look Like Right Before It Hatches?

Right before hatching chicken eggs, you’ll see that most of the space inside their eggs is taken up by the developing chick. The air cell at the larger end will also be noticeably bigger. 

Candling right before hatching isn’t generally advised, as you can disrupt the hatching process. But if you do, expect to see very little light passing through, as the chick takes up most of the room.

What Is the Black Spot on Egg Candling?

When you’re candling, a black spot often indicates a developing embryo inside the eggs. However, it can also mean that there’s a problem like bacterial infection. 

If you see a black spot along with a web of blood vessels, it’s likely a growing chick. If there are no blood vessels, and the spot seems to be floating, you might have an issue that needs further investigation.

Does Candling Eggs Harm Them?

In general, candling is a non-invasive and harmless way to check the development of a chicken’s eggs. However, it does pose some risks. 

The longer you take and the more you handle the eggs, the more you expose them to temperature changes and potential breakage. Always be quick and careful to minimize these risks.

Final Thoughts

Candling eggs is an important skill for anyone serious about poultry care, providing you with a unique look inside the shells to assess the health and development of your would-be chicks. 

Understanding the need to candle the eggs is as crucial as mastering the best times and methods for doing so.

From identifying the contents to understanding developmental markers, candling gives you insights that can significantly improve your poultry-rearing efforts. 

It’s a compelling mix of art and science, steeped in tradition yet thoroughly modern in its importance for ensuring the health of your flock.

So whether you’re a newbie or an old hand at raising chickens, we hope this guide has deepened your understanding and skills in candling eggs. 

We’d love to hear about your experiences or any tips you may have, so please feel free to leave a comment below!

Leave a Comment

You may also like