When To Candle Eggs? Common Question And Answers

Helen Skeates
Helen Skeates
19 min read

Are you a novice when it comes to the art of candling eggs? Alternatively, you may have just started working in the poultry industry and thought that egg candling was part of the job description. We’re here to assist you understand vital topics like when to candle eggs, no matter what the situation.

Be aware of the circumstances in which an egg should be candled and when it is best to avoid doing so. For example, did you know that between the eleventh and fourteenth day of incubation, you should avoid lighting candles on eggs? Embryos can get stuck in the egg’s length axis if this happens.

To put things into perspective, can you see how crucial it is to know when to correctly light an egg? After that, we’ll go over all you need to know about egg candling, including how often you should do it and other amusing facts. In order to get started, let’s go through the fundamentals of egg candling.

Why Candle an Egg?

Incubating eggs to produce chicks for a farm’s laying hens necessitates regular egg-candling to ensure that the eggs are fertilized and growing properly. Embryos that have ceased growing and are referred to as “quitters” have the potential to decay in your incubator, causing it to smell. Alternatively, they may explode, infecting the rest of the eggs with pathogens.

Chicken Egg Candling Day 3 - YouTube

To monitor the development of the embryos, it’s a good idea to look at the eggs.

You can use a candle to test the freshness of your eggs if you’re a small-scale farmer selling them. You’ll need a powerful light for this task, but all you’ll be checking is the air sac’s diameter. The air sacs in older eggs are larger. A small farm egg business relies on selling only the freshest eggs, as well as washing, collecting, and storing the eggs properly.

How to Candle an Egg

In order to see your eggs clearly, you will need a bright light and a dark room.

Egg candling devices can be purchased from poultry supply or farm supply stores, but you can also create your own.. a 60 watt incandescent bulb with a coffee can Make a one-inch-diameter hole in the top of the container. Another option is to use a bright flashlight and cut a one-inch diameter hole in the centre of a piece of cardboard to conceal the entrance.

If you’re hatching a lot of eggs, specialized candling devices like the Ovascope can make the procedure a lot easier and more time-efficient.

In order to see what’s inside one of the eggs, gently pick it up and place it in front of a window. Using a flashlight, hold the egg’s bigger end against the light and turn it slowly. Take a look inside the egg to see what’s happening inside the womb. You don’t want to overheat the embryo by holding the egg up to the light for too long.

Restore the egg to its incubator after you’ve finished inspecting it.

Eggs should not be taken out of the incubator for more than twenty to thirty minutes at the most.

What to Look For

Try to identify these sections of the egg:

  • a bag of air
  • The egg’s shell has pores.
  • Yolk
  • Red ring or blood vessels around the yolk
  • the developing embryo

If you look at a fertilized, growing embryo inside the first week or on day seven, you’ll see a visible blood vessel network. Afterwards, you’ll be able to see the eye, a shadow that suggests its body, and potentially even movement.

Rings around the yolk of “Quitters,” or embryos that have ceased development, are reddish in color. Although it can be difficult to tell the difference between blood spots and growing embryos, they may show blood spots or streaks as well. Take these out of the incubator.

No blood vessels, no ring, and no spots in the yolk indicate that the egg was not fully fertilized. Discard them after they’ve been removed from the incubator (not good for eating).

Make a note of your findings in a journal and assign a number to each egg.

Returning an egg that you aren’t sure about to the incubator is fine as long as you take a note of the number so you can check it again later.

What is Egg Candling?

It is possible to see the development of an embryo inside an egg by using the technique of candling. To accomplish this, place a powerful light source behind the egg and shine it directly on the egg’s shell to reveal details. Because the initial sources of illumination were candles.

It’s a modern egg candle or candle lamp that has a narrow beam. LEDs have become increasingly popular because of their tremendous brightness, efficiency, and long lifespan. Bulb replacement is no longer necessary, and compact, battery-powered devices are no longer an issue.

Right out of the box, you can use it. Cool light rather than a lot of heat can also be produced by these LEDs. Broiler eggs must be cared for because of the strong demand for them.

Importance of Egg Candling

When you use egg candling, you can see what is happening inside the egg. It keeps track of ovulation, embryonic growth, and weight loss. It is also possible to identify and remove non-viable eggs, which may be infertile or have died prematurely.

Even bad eggs that explode and spread hazardous bacteria to the herd can be avoided. To avoid these issues, you must know when to candle eggs. Imagine the sorrow of losing all of your eggs because you failed to check on one.

Because they’ve been removed from the incubator, candling your eggs does no harm. When you think about it, the mother doesn’t always have to be on top of the eggs. For a little while, think that you’re holding a candle to them while they’re gone.

Water evaporation from the eggs should cause an increase in the size of the air sacs during hatching. Eggs should lose roughly 13% of their weight during the hatching process. On different incubation days, if the humidity is close to ideal, the airbags should rise.

If the airbag is more visible than usual, don’t be alarmed; the incubator’s humidity may be too low. Do not panic. To slow down the rate at which water evaporates from the incubator, you should raise the humidity level. Contrary to popular belief, if the airspace is particularly constrained, the opposite holds true.

When To Candle Eggs?

It’s possible to light the eggs after five days of hatching, and thereafter do so every few days. The best outcomes are obtained when egg candling is performed in low or no light. The larger end of the egg, next to the bladder, is the best place to place the candle.

Incubation time of 7-10 days is optimum for candling eggs. However, embryos are extremely fragile in the first week, so you must wait until this essential period has passed before you can conceive. After approximately a week, you’ll have a better idea of what’s going on.

Blood arteries dilate and embryos form as eggs are rotated. There will initially be little patches with an increased artery network on the surface of the eggs that are still viable. In order to remember when to candle eggs, make a calendar note of these important dates.

When to Candle Eggs During Incubation?

Place healthy and undamaged eggs into the incubator first. Every seven to ten days, fertility is checked and cleanses are eliminated. Just sixteen days before hatching, you can do it again.

Get rid of eggs that haven’t hatched. It is important not to let the newly hatched chicks break their eggs, since this could result in a terrible odor. Candling eggs prior to hatching may also assist uncover egg flaws that may prevent them from hatching.

Inspect for missing yolks, cracks, broken air sacs, or shell defects. It is common for embryos to begin to develop, only to cease at some point. It eliminates sawdust and prematurely dead eggs from the seven-day indication candle.

Eggs that have been candied the day before pecking can help get rid of those who have already given up. If you don’t know how often you should candle eggs, you won’t know how often you should.

Candling Pictures | Scratch Cradle

Is Egg Candling Harmful to Eggs?

Not normally, but it can happen if someone is negligent or takes too long. An egg can be ruined if it is left on a hot light bulb for too long. Similarly, eggs that have been incubated for an extended period of time may perish. If you need to ignite a big number of eggs at once, this is an issue. If you utilize a lot of candle eggs, you’ll have a greater chance of them breaking or getting damaged. Put a soft towel under your work area as a precautionary measure.

How-To Candle Eggs and Why It Is Important

If you’ve never worked with chickens before, you might believe that candling eggs is nothing more than a kid’s 4-H project. Alternatively, you may have never heard of the term “candling.” Candling eggs at regular intervals allows you to keep an eye on the embryo’s progress, which can save you a few headaches in the long run.

Egg candling isn’t difficult. Only a few ingredients and a few minutes are required. You’ll need a dark place, a powerful light, and the egg you intend to candle to get the job done.” GQF Manufacturing’s Cool-Lite Tester is the light we suggest you use. The egg is less likely to be dropped or cracked as a result of being handled for a shorter period of time with this equipment. It’s a basic design, but it works well because it keeps light from leaking out of the bottom of the egg, giving you a clear view of what’s inside.

It’s not difficult, yet there is something to it, as previously stated. To correctly and confidently candle your eggs, there are a few things you need know.

Preparing to Candle Eggs

1. Consider the reasons why you are candling your eggs.

A candle is used to track the development of each embryo after fertilization. Look within the shell for certain features by flashing a bright light very next to the egg. There is no guarantee that all of your eggs will hatch. A small percentage of eggs never mate. “Yolkers” are the name given to these eggs. “Quitters” are eggs that stop growing during incubation. “Winners” are the fertilized, correctly growing eggs.

It’s critical to remove eggs from the incubator as soon as you suspect they contain a yolker or quitter. The eggs will go bad if you don’t. If the eggs are allowed to decay in the humid environment of the incubator, gas can build up and cause an explosion. It’s not just a disgusting stench; the bacteria from the rotten eggs is also spread to the healthy egg yolks in the process. As a result, the embryos and the chicks are vulnerable to illness.

2. Gather the supplies you need to candle your eggs.

Candled eggs, as the name implies, are made by lighting a real candle inside an egg. Using the light from the candle, they would examine the egg’s interior from a distance. In today’s world, a candle is no longer necessary; instead, you’ll need a very bright light that can seal the egg tightly from the outside. The Cool-Lite Tester is one of the best lighting instruments available.

3. Establish the schedule to candle your eggs.

The majority of poultry growers use a double-candle method. Around six to eight days after they’ve been placed in the incubator, they will begin to feed themselves. Depending on the breed of eggs, the first candling time may vary slightly. Brown eggs should be candled later than white eggs because the dark shell makes it more difficult to discern early development. A week after the first candling, there will be a second candling. After the first candling, any eggs that didn’t develop or those you weren’t sure about will be identified in this second candling. Make a note of any eggs after the second candling that you are doubtful about and re-candle two days later. After 14 days, it’s recommended not to handle the eggs.

Steps in Candling Eggs

1. Place the light on the egg.

It’s best to do your candling in complete darkness. Cool-Lite testers can be used to see if an egg’s air sac is developing at its bigger end. Rotate it gently until you get the best seal against the egg and the best view of the egg’s insides.

2. Identify the “winners.”

The effective embryonic development of the eggs is what determines the winners. In order to tell if the egg is a victor, check for a white vascular network. In the midst of the blood arteries, the embryo is clearly seen as a black outlines. You may even be able to see the embryo’s dark eyes or the embryo’s movement. Both of these are indications that the egg is going to be a winner.

3. Identify your “quitters.”

The term “quitter” refers to an embryo that has ceased to develop at some point during incubation. The blood ring, a clearly defined crimson circle on the inside of the shell, is the best way to identify a quitter. An embryo’s blood vessels peel out from the embryo and rest against the eggshell’s interior when it dies. Dark red streaks inside the egg might also tell you whether a person is a quitter. A healthy embryo’s streaking can be confused for that of a quitter, therefore the blood ring is the best way to detect one.

4. Identify the “yolkers.”

Yolkers are unfertilized eggs that will never grow into embryos. It will appear clear and undeveloped when viewed via a candle. It’ll shine. Blood vessels, a dark embryo, or even a blood ring will not be present. As soon as you put your eggs in an incubator, they’ll look exactly the same.

5. Toss out the “yolkers” and the “quitters.”

Do not re-incubate an egg that is a yolker or a quitter after you know for sure that it isn’t viable. Whenever in doubt, return it to the incubator and inspect it on day 14 to be sure. Toss the egg out if there are still no signs of growth.

Let us know what you think

Candling is essential if you want to keep your incubator free of the foul surprise of an exploded egg. Maintaining a clean incubator is as simple as following these steps: A warm, humid atmosphere full with eggs can only be as clean as it is possible to make it appear.

An egg exploding in your incubator could be a scary experience. I’m interested in learning more about the process of candling eggs. Please share your thoughts in the comments section below!

Visit our Cool-Lite Tester page to learn more about the light we highlighted in this article.


When should you first candle an egg?

After 6-8 days in the incubator, they will be able to eat solid food for the first time. Depending on the breed of eggs, the first candling time may vary slightly. Brown eggs should be candled later than white eggs because the dark shell makes it more difficult to discern early development.

Can you candle eggs before Day 7?

In order to ensure the health of the embryo inside the egg, you simply need to check it a few times throughout incubation. On days 7 and 10, and then again on day 18, it’s a good idea to check the eggs for cracks.

How many times should you candle chicken eggs?

Incubation: How many times should you check on the eggs? During incubation, you should light a candle three times. Before putting your eggs in the incubator, check to make sure they are healthy and not damaged in any way. A fertility check and clears removal should be performed once every 7 to 10 days.

Should you candle eggs before selling?

The first step in selling eggs from your own backyard hens is learning how to properly candle them. With a backyard flock of hens, you’ll always have fresh eggs on hand. Nevertheless, if you plan to market the eggs, Georgia law mandates that they be candled. The freshness of an egg can be gauged by looking at how much air there is inside the shell.

Does candling hurt eggs?

Your eggs will not be harmed by using a candle. Incubating eggs can be taken out of the incubator for a short period of time each day to be candled, just like a mother bird would. A larger air sac should form throughout incubation as the egg loses water.

Day 6 Candling (Ducks) / Can only see the yolk | BackYard Chickens - Learn How to Raise Chickens

How do you know if a chick has died in an egg?

As long as the yolk remains in the egg, you’ll be able to identify if it’s already absorbed into the body (as it will be when the chick starts pipping). The chick’s head moves to face the air cell at the top of the egg during the last two days of incubation.

How can you tell if a duck egg is fertile before incubating?

In order to tell if the egg is fertile, you should notice a black area in the middle of the egg, surrounded by spider-like veins. A yellow yolk should be visible without any evidence of an embryo or veins inside an egg if it’s not.


Egg candling is one of the procedures used in broiler production. Egg candling, on the other hand, isn’t as simple as igniting an egg and observing what happens inside it. Candle eggs at the appropriate moment, know what to expect, and all the other things you need to know.

Helen Skeates

Helen Skeates

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