Candling eggs is a fascinating and essential step in the hatching process. This practice allows you to monitor the development of the embryos and troubleshoot potential issues, ensuring the best chance of success. Whether you’re new to hatching or a seasoned pro, learning the art of candling can make your incubation experience even more rewarding.
Here we’ll cover everything you need to know about egg candling - with a special focus on shipped eggs - including tools, techniques, and what to look for during each stage.
What Is Egg Candling?
Candling involves shining a bright light through an egg to observe what’s happening inside. Originally done with candles (hence the name), today’s candling uses specialized lights or flashlights that offer a much clearer view without exposing the eggs to heat damage.
Through candling, you can evaluate embryo development, monitor air cell growth, and identify non-viable eggs. It’s not just practical; it’s also a magical way to witness the early stages of life forming inside an egg.
Tools You’ll Need for Candling
To get started, you’ll need the following tools for effective candling:
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Candling Lamp or High-Lumen Flashlight
Opt for a bright, focused light source that can shine clearly through the egg’s shell. LED candling lights are a popular and safe choice. -
A Dark Room
Conduct candling in a dark environment to improve visibility and minimize distractions. -
A Steady Hand
Hold the egg carefully, pointy side down, and gently angle it toward the light source during the process.
Pro Tip: Avoid using lights that emit excessive heat, as this could harm the developing embryo.
Candling Shipped Eggs Upon Arrival
When hatching shipped eggs, candling upon arrival is an essential first step. Shipping can cause internal disruptions, including damage to the air cell, which is a critical part of the egg’s internal structure. Here’s how to check shipped eggs and what to look for:
How to Candle Shipped Eggs
Prepare to candle each egg in a dark room with your light source. Focus the light near the blunt end of the egg where the natural air cell forms. Slowly tilt and rotate the egg to get multiple views of its interior.
Identifying Loose or Detached Air Cells
A healthy air cell typically stays fixed at the fat end of the egg and appears as a clear, stable pocket of air. However, shipping can cause the air cell to loosen or detach, resulting in a freely moving air pocket that shifts as the egg is tilted.
Detached air cells may look wobbly or seem to slide along the eggshell. This issue can also appear as irregular or multiple separated air pockets, floating freely inside the egg.
What to Do with Detached Air Cells
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Resting Period: Place the eggs upright (pointy end down) in an egg carton and allow them to rest for 12-24 hours at room temperature. This can help some loose air cells stabilize.
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Incubation Strategy: For eggs with confirmed detached air cells, avoid turning them for the first few days of incubation. Instead, incubate them upright and reduce handling to prevent further disruption.
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Monitor Through Candling: Recheck these eggs after a few days in the incubator. Gradually, some air cells may reattach or stabilize enough for normal development to continue.
Handling shipped eggs with care and recognizing detached air cells early on gives you a better chance of a successful hatch.
When to Candle Eggs
Candling can be done multiple times throughout the incubation process. Each stage provides unique insights into the development within the egg.
Day 7 - The First Check
At this point, the embryo has started to develop, and you should see the following:
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Blood Vessels
A healthy egg will show a clear network of blood vessels branching out from the embryo, often referred to as a “spider-like” pattern. -
Dark Spot (the Embryo)
You may notice a small dark spot in the middle of the veins—that’s the embryo! -
Movement
Gently tilt the egg and watch for subtle movements, an indicator of a thriving embryo.
Eggs that appear clear with no visible veins or a dark ring around the yolk may not be fertile or viable and should be removed from the incubator.
Image used with permission from Brinsea.com
Day 14 - Checking Progress
By day 14, the embryo has grown significantly. Here’s what to look for at this stage:
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Larger Embryo
A healthy embryo will occupy much more space within the egg and may appear as a dark mass. -
Veins Still Visible
While the veins may be less prominent, they should still be noticeable near the shell’s edges. -
Air Cell Growth
The air cell at the blunt end of the egg should have expanded since day 7, a sign of proper development and moisture loss.
Remove any eggs showing signs of infection, such as a foul odor, discoloration, or a “weeping” liquid.
Image used with permission from Brinsea.com
Day 18 - Final Candling Before Lockdown
The final candling session is crucial before entering the “lockdown” phase (i.e., the last three days of incubation when turning stops). Look for the following signs of readiness:
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Fully Occupied Shell
The embryo should have filled most of the egg, leaving only the air cell visible. -
Defined Air Cell
The air cell should be clearly visible and have grown to its final size, indicating the egg is ready for hatching. -
Minimal Movement
Movement may be minimal at this stage due to the limited space inside the shell, but this is completely normal.
Candling at day 18 also allows you to double-check for any eggs that haven’t developed properly to avoid potential contamination in the incubator during the hatch.
Image used with permission from Brinsea.com
Tips for Candling Success
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Be Gentle
Handle eggs carefully to avoid cracking or damaging the shell. -
Minimize Exposure
Limit the time eggs spend outside the incubator to maintain a stable temperature and humidity level. -
Practice Patience
Candling gets easier with practice. Take your time and marvel at what you see!
Troubleshooting Common Issues
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Detached Air Cells
Eggs with detached air cells (common in shipped eggs) should be incubated upright, with gentle monitoring during candling to ensure the air cell gradually stabilizes. -
Blood Rings
A blood ring is a sign that the embryo has stopped developing. These eggs should be removed immediately to prevent contamination. -
Clear Eggs
Eggs that show no signs of development by the first candling session are likely infertile or damaged from shipping and can be removed.
Why Candling Matters
Candling eggs isn’t just about curiosity; it’s a vital step to ensure a successful hatch. Regular checks allow you to assess embryo health, manage incubation conditions, and identify potential problems before they impact the rest of the batch.
Final Thoughts
Candling eggs is an exciting and educational part of the hatching process. By knowing when and how to candle, as well as what to look for, you can gain a deeper appreciation for the miracle of life while giving your eggs the best chance at success.
Happy candling, and best of luck with your hatch!
