The Complete Beginner’s Guide to Egg Candling

By Chicken Pets on
The Complete Beginner’s Guide to Egg Candling

Welcome to “The Complete Beginner’s Guide to Egg Candling”! In this blog post, we will explore the fascinating world of egg candling, providing you with all the essential knowledge to confidently monitor the health of your backyard chicken eggs.

The Complete Beginner’s Guide to Egg Candling

Egg candling is a simple, non-invasive technique used to inspect developing eggs, allowing you to check their health and progress. The process involves shining a light through the eggshell to reveal the contents inside, so you can easily identify fertile eggs, track the growth of embryos, and remove any non-viable eggs from your incubator.

Importance of Egg Candling

Egg candling is a valuable skill for anyone raising chickens and looking to hatch their own eggs. By identifying fertilized and non-viable eggs early, you can improve hatch rates and maintain a healthy batch of chicks. It’s an essential part of the incubation process and helps ensure a successful, healthy hatch for your backyard flock!

Essential Equipment for Egg Candling

Before diving into the process, let’s gather the necessary tools for egg candling. Fortunately, you don’t need much, and it’s quite affordable.

Egg Candler or Flashlight

An egg candler is a specialized flashlight designed for candling eggs. They typically have a strong LED light source that is focused by a cone-shaped attachment. This helps in directing the illumination towards a small area, such as an egg. Alternatively, you can use a regular flashlight and make your own homemade candler with dark-colored cardboard or paper, forming a cone around the light source.

Dark Room or Area

A dark room, closet, or any space with minimal light is optimal for candling eggs. This allows the light source to better penetrate the eggshell and reveal the contents inside.

Notepad or Chart

Keeping records of your egg candling findings can be helpful in tracking the progress of the embryos. Note down dates and observations as you go, which will help you make better decisions for your flock.

Preparing for Egg Candling

Before starting the egg candling process, follow these simple steps to ensure a smooth and efficient experience:

  • Choose a darkened area or room for candling.
  • Set up your egg candler or flashlight, making sure it’s adequately charged or has fresh batteries.
  • Wash and dry your hands before handling the eggs to avoid transferring any bacteria.
  • Ready your notepad or chart for recording observations.

Step-by-Step Guide to Candling Eggs

Now that you have your equipment ready, let’s dive into the actual process of egg candling. Here’s a step-by-step guide on how to do it:

  1. Choose the right time: Start candling eggs around the 7th day of incubation. At this stage, it will be easier to identify whether the eggs are fertile or not. You can also candle again around the 14th day to confirm the eggs’ progress.
  2. Dim the lights: Turn off any additional light sources in the room, so only the egg candler or flashlight is providing light.
  3. Hold the egg: Carefully pick up an egg from the incubator, holding it with your thumb and index finger on either side of the air cell (the large end of the egg). Make sure your hands are clean to prevent spreading bacteria to the egg.
  4. Direct the light: Place the light source on the air cell end of the egg, ensuring that the cone is covering the entire surface of the shell. This will allow the light to penetrate the eggshell effectively.
  5. Inspect the egg: Look for specific signs and features inside the egg, which we will cover in detail below.
  6. Record your observations: Take note of any findings, such as development progress or potential issues, before returning the egg to the incubator. This will help you track the health of your eggs throughout the incubation process.
  7. Repeat: Continue candling each egg in your incubator, taking your time to minimize handling and ensure accurate observations.

Interpreting Egg Candling Results

Understanding what you see during egg candling is crucial to ensure the health and success of your hatch. Here are some common observations and their interpretations:

Fertile and Developing Eggs

A fertile egg will show a network of blood vessels and, depending on the age of the embryo, a small, dark mass that represents the developing chick. If the embryo is moving or twitching, that’s a good sign, indicating a healthy and viable egg.

Infertile Eggs

An infertile egg will appear clear and show no signs of blood vessels, veins, or a developing embryo. You may see a small, opaque mass known as the yolk, but otherwise, it will remain mostly transparent.

Early Deaths and Blood Rings

Occasionally, you may come across an egg containing a blood ring, which indicates an early death during the incubation process. The egg may have a dark, thick ring or a red ring that encircles the yolk. These eggs should be removed from the incubator.


A “quitter” refers to an egg where the embryo has stopped developing. It typically appears as a dark mass with no movement and may have a spotty network of blood vessels. These eggs should also be removed from the incubator.

Empty or Cracked Shells

Empty shells may occur if eggs were not properly fertilized before being placed in the incubator. They will appear entirely clear and should be removed. Similarly, if you notice any cracks in the shell during candling, the egg is most likely not viable, and you should remove it.

Common Egg Candling Questions

As you begin your journey in egg candling, here are some common questions and their answers to provide additional guidance:

How often should I candle my eggs?

It’s best to candle your eggs at least twice during the incubation period, around the 7th and 14th days. Candling too frequently may cause potential stress to the developing embryo and affect the temperature and humidity within the incubator.

Can I still eat an egg after I’ve candled it?

If you’ve candled an unincubated egg that you simply wanted to check for freshness, the egg can still be consumed. As long as the candling process was performed quickly and cleanly, the egg remains safe to eat. However, once an egg has been incubated, it is no longer suitable for consumption.

Is it difficult to learn egg candling?

Egg candling is an easy skill to learn but may require practice to become proficient at identifying development stages and potential issues. By regularly practicing and paying close attention to changes in the eggs, you’ll soon become a confident egg candler.

Tips for Successful Egg Candling

To ensure successful egg candling and a healthy hatch, follow these helpful tips:

  • Keep your incubator clean and well-maintained to prevent bacteria growth and maintain optimal temperature and humidity levels.
  • Limit your candling frequency to minimize disturbance to the developing embryos. Stick to the recommended timeframes of the 7th and 14th days.
  • Always handle eggs carefully to prevent accidental damage to both the shell and the developing chick.
  • Stay organized and keep records of your candling observations. This will allow you to track the progress and health of each egg, making the process more manageable and less stressful.

By understanding the process of egg candling, proper equipment, and knowing how to interpret your observations, you will be well on your way to ensuring a successful and healthy hatch for your backyard flock. Remember to be patient, enjoy the process, and keep learning as you nurture your growing flock.

Egg Candling Safety Precautions

While egg candling is generally safe, taking precautions will ensure the well-being of both you and your developing chicks. Here are some safety tips to follow during the egg candling process:

  • Cleanliness: Always wash and dry your hands thoroughly before handling eggs to avoid transferring bacteria to the shells. Incubators can also collect bacteria, so ensure regular cleaning and maintenance.
  • Handling: Hold eggs gently but securely, taking care not to drop or crack them. Be especially cautious when handling the air cell end, as excessive pressure can damage the developing embryo.
  • Time management: Work efficiently during egg candling to minimize time spent outside the incubator. Prolonged exposure to room temperature and varying humidity levels can negatively impact the developing chicks.

Understanding Egg Development Stages

Egg development occurs in stages, and knowing what to expect at different points in the incubation process can help you better interpret your candling observations:

Day 1-4:

During this early stage, it’s difficult to see any significant changes inside the egg. Although blood vessels begin to form, they’re often too small to observe using egg candling.

Day 7:

By day 7, embryos have grown in size, and their blood vessels are more noticeable. You may see a spiderweb-like network of blood vessels surrounding the embryo, which can be a great indication that the egg is fertile and developing.

Day 14:

At this stage, the embryo has grown considerably larger and occupies more space inside the egg. The blood vessels are now more apparent, and the embryo will show visible movement. The air cell has also increased in size, which is crucial for the chick to breathe before hatching.

Day 18-21:

During the final stage of incubation, the embryo takes up most of the egg’s interior. Candling at this point may show a completely dark interior with only the air cell visible. The chick moves into the hatching position and prepares to break free from the shell.

When to Remove Unhealthy or Non-viable Eggs

The timing of this step matters for the health of the remaining eggs:

  1. Remove any eggs with cracks or leaks immediately, as these can harbor bacteria that may spread to healthy eggs.
  2. If you identify a non-viable egg during candling, remove it from the incubator as soon as possible. Unhealthy eggs can release harmful gases and contaminate the environment for the viable eggs.
  3. When removing an unhealthy egg, handle it carefully to avoid breakage, and clean your hands before proceeding with the candling process.

By incorporating these additional tips and insights, you’ll be better equipped to manage a successful hatch and care for your backyard flock. Egg candling is an essential skill for any poultry enthusiast, and with practice and patience, you will master it in no time.

Frequently Asked Questions

The world of egg candling may seem overwhelming at first, but we’ve put together answers to the most frequently asked questions to help clear up any confusion and get you started on your egg candling journey.

1. How do I candle a dark or brown-shelled egg?

Dark or brown-shelled eggs can be more challenging to candle due to their thicker shells. Using a high-powered egg candler or flashlight can help penetrate the shell, but the developmental features may be more challenging to identify. With experience, however, you’ll get better at interpreting the shadows and markings inside these eggs.

2. Can I use a phone flashlight for egg candling?

While a phone flashlight may work for candling lighter-shelled eggs, it might not be powerful enough for darker eggs. It’s best to use a dedicated egg candler or a high-powered flashlight for optimal results.

3. Can I candle eggs under a broody hen?

Yes, you can! However, be mindful of the broody hen’s stress levels when removing the eggs from under her, and work as efficiently as possible. Avoid candling the eggs too often to prevent excessive stress for the hen and the developing embryos.

4. What is the ideal room temperature for egg candling?

There isn’t an ideal room temperature for egg candling itself, but it’s crucial to maintain a stable temperature inside the incubator. When candling eggs, work quickly and efficiently to minimize the time they spend outside the incubator and avoid temperature fluctuations that may harm the developing embryos.

5. Can I candle eggs after the 14th day?

While you can candle eggs after the 14th day, it’s generally not necessary as the embryo takes up most of the egg’s interior by this point. Candling after day 18 is not recommended, as it can disrupt the chick’s position and preparation for hatching.

6. How do I determine the age of an embryo?

Embryo age can be determined by observing the size and appearance of the embryo, blood vessels, and air cell during egg candling. Familiarize yourself with the various stages of egg development to accurately determine an embryo’s age.

7. Can I reuse an egg candler?

Absolutely! Egg candlers can be reused many times, making them a cost-effective investment for those raising backyard chickens and hatching eggs regularly.

8. Is it safe to remove the eggshell after candling?

Removing the eggshell during or after candling is not recommended, as doing so will expose the developing embryo to potential harm or damage. Handle eggs with care during the candling process and limit handling to prevent stress and accidental breakage.

9. Can egg candling spread diseases or parasites?

Egg candling itself is unlikely to spread diseases or parasites as long as proper precautions are taken. Always wash your hands before and after handling eggs, clean your egg candler, and maintain a clean incubator environment to prevent contamination or disease transmission.

10. Do I need to sanitize my egg candler between uses?

While it’s not mandatory to sanitize your egg candler between uses, wiping it down with a damp cloth after use to remove any residue can help maintain a clean environment and minimize the risk of contamination.

11. How can I improve at egg candling?

Practice makes perfect! As you gain experience in egg candling, you’ll get better at recognizing developmental features and identifying viable and non-viable eggs. Building familiarity with the process and different egg development stages is vital for mastering this skill.

12. Can a cracked egg still develop?

A cracked egg is unlikely to develop, as the crack can allow bacteria to enter and compromise the developing embryo. It can also result in insufficient humidity and temperature for proper development inside the egg. It’s best to remove cracked eggs from the incubator to prevent potential harm to the other eggs.

13. Can egg candling determine the chick’s gender?

Egg candling cannot definitively determine a chick’s gender. However, experienced poultry keepers may make educated guesses based on shell markings or features observed during candling. To accurately determine a chick’s gender, it’s best to wait until they hatch or seek professional assistance in sexing the chicks.

Like what you see? Share with a friend.


Popular posts from the hen house.

Egg-cellent job on making it to the footer, welcome to the egg-clusive chicken club! At, we are a participant in the Amazon Services LLC Associates Program and other affiliate programs. This means that, at no cost to you, we may earn commissions by linking to products on and other sites. We appreciate your support, as it helps us to continue providing valuable content and resources to our readers.