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The First Week of Incubation: Candling Chicken Eggs Day 7

So, you’ve decided to hatch some chicks, you’ve set your eggs in the incubator, and now you’re just dying to know if those little embryos are developing? We’ll, you’re in luck, because we have the inside scoop on candling eggs on day 7 and everything you might see when you look inside!

By the time day 7 rolls around on your incubation calendar, the teeny chicken embryos will have already done an extraordinary amount of work. In just seven days the tiny little life form has already developed into a recognizable chick, just very, very small.

In this post you’ll find out exactly how to candle an egg, and what you can expect to see inside during the first week of incubation!

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An egg being candled with a chick inside.

What to Expect Candling Chicken Eggs on Day 7

What does it mean to candle eggs?

When you’re incubating eggs, it helps to have some idea what’s going on inside, but you can’t exactly crack them open to see, right? So instead, we shine a bright light through the egg to see the contents inside. The name candling actually comes from the olden days when chicken farmers would use an actual candle to see inside the egg. These days we have much more convenient and safe ways of seeing the embryo development inside the egg.

During incubation, candling is done a few times to see the development of the embryo. This process also helps you to identify bad eggs, infertile eggs, or rotten eggs so you can get rid of them.

Candling eggs is the most exciting part of the incubation process. It’s so fun to see the baby chicks developing inside, and it’s a truly educational experience for kids. The interior of an egg is fascinating to look at, and it’s especially fun when you can see the developing chick moving around in there!

A developing chicken egg being candled.

How do you candle eggs?

Most importantly, before you ever handle fertile eggs that you’re incubating, make sure to wash your hands really well with antibacterial soap and rinse them clean.

Although eggs may seem solid to the naked eye, eggs are actually porous on their surface.

Handling the eggs with unclean hands can cause bacteria on your hands to transfer to the developing embryo inside. Don’t take this risk, make sure you wash super well!

To candle your eggs, you can either use a special egg candling lamp or a bright flashlight.

The benefit to the egg candler is the ease of use and it’s quite a bit safer for the egg. Some eggs are easier to see inside of than others. For example, white and light brown eggs are usually very clear, whereas dark brown eggs, and green/blue eggs are very hard to see inside.

You may want to use the egg candler for these darker eggs, as the bright light source will give you the best view of the embryo.

The egg candler will cradle the egg for you so it’s mostly hands free. They also tend to be brighter than your average flashlight.

If all you have is a flashlight, don’t fear! Candling eggs with a flashlight is very easy and works pretty well.

Make sure to candle eggs at night and do it in a dark room. Then simply turn on your light and cup the light beam with your hands to funnel the light. Hold the egg with that same cupping hand over the flashlight and voila! You’ll be able to see inside the egg!

A view of the air sac at the end of the egg.

How often should I candle eggs?

You only need to candle the eggs a few times during the 21 days of incubation to make sure you have a healthy embryo growing inside. It’s a good idea to candle the eggs on day 7 and day 10, then again on day 18 right before you set the eggs into lockdown.

Don’t handle the eggs at all after day 18, as the chicks inside will be prepping themselves for hatch day and shouldn’t be disturbed.

The candling process certainly doesn’t need to be done every day. Handle the eggs as little as possible during incubation to avoid contaminating or breaking the eggs.

If you can hold off on the temptation to candle them constantly (I know this is super hard to do!) it will be better for the eggs and developing chicks.

If your eggs are being incubated by a mother hen, it’s even more important to limit the number of times you candle the eggs. It’s best not to disturb momma hen more than necessary, especially if it’s her first time going broody!

What will I see when candling eggs on day 7?

On day 7 of candling eggs, you should start to see the beginning stages of development of your chick embryo.

If the embryo is developing, you will see a network of blood vessels running from side to side across the egg. Attached to the veins you might see a dark spot, which is the developing embryo.

You may even be able to see the embryo’s eye, which will be a large black circle.

If it’s a fertilized egg, you’ll also see an air sac, or air cell on one end of the egg, usually on the larger end of the egg. The air sac will look like a light circle. You may even see movement at this stage if you look carefully!

A chicken embryo and veins inside the egg.

If there is no developing embryo inside the egg when you candle it, you’ll simply see the yolk of the egg floating around.

You may see a black ring in the egg, called a blood ring (like in the photo below), which means that the embryo started developing but then died. These eggs can be disposed of right away.

We usually bury them in the yard, as they can’t be composted and we don’t want any animals getting ahold of them and making a mess. If you don’t dispose of these eggs, they’ll continue to rot in the incubator.

A blood ring inside a candled egg means that the embryo has died

What if I can’t tell what I’m looking at?!

It can be really hard to tell this early in incubation whether or not the chick is starting to develop, especially if you’re trying to candle eggs with a dark shell like blue, green or dark brown eggs.

If you can’t quite tell what’s going on inside the egg, there’s nothing wrong with putting it back into the incubator and trying again in a few days.

Our go-to strategy when candling eggs on day 7 is to remove any eggs with a blood ring in them and leave the rest. We then candle again on day 10 to get a clearer picture of what’s going on inside of the egg.

You may need a brighter flashlight or a few more days to truly see what’s going on inside. Give it some time and be patient, especially if you’re a beginner at this whole chick hatching game!

Want to find out what happens next?

We’re only taking you up until day 7 of incubation in this post, but if you’re curious, our friends over at 104 Homestead wrote a great post detailing what’s coming next for your teeny little embryos! Check it out here!

If you’re incubating eggs and hatching chicks, we want to hear about it! Comment below with your experience, we love to chat chickens!

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Sandra O’Brien

Tuesday 21st of June 2022

My 1st hatch I got 8 out of 26. My second hatch I got 2 out of 24. I just today 6/21/2022 started my 3 hatch. I’ve learned alot along the way so y’all need to wish me luck 🍀

Regina Smith

Wednesday 23rd of March 2022

Hi! Im new at incubating chicken so excited about it..I have an electric getting it prepared for fresh laid eggs...I cant wait to see the outcome.I have 11 hens,its called the "chick-Inn, and 1 Rooster,his name is MR.He is a very happy Rooster.I am excited to share the progress as time goes on!!


Thursday 24th of March 2022

Fun! Good luck to you! It's one of the most exciting and rewarding things you can do!

Milo boy

Sunday 27th of June 2021

Hi I really need help can I start inculbating an egg that have been inculbated for 4 days by the mother hen, because I collected her eggs and puted it inside and incubator I made myself and after a day the vesin in the egg were not more clear than before


Thursday 7th of January 2021

i have bought eggs from the store, i tried to incubate an oval shaped egg. Then when i candled it my ate said it was fertile . how?


Friday 8th of January 2021

I'm not sure I understand your question? Some stores sell eggs that could have been fertilized, it all depends on how the chickens that laid them are raised, if they're raised with roosters in a free range situation they could certainly be fertilized before you buy them. As long as they are fresh and haven't been refrigerated for long they can be incubated.


Monday 23rd of November 2020

I am at day three of incubating chicken eggs. This is my first time doing this so here's my question: Should I turn off the incubator while candling the eggs or leave it running? May sound like a strange question, but I have yet to get an answer so I hope you can give me one. I just want to do this right.


Friday 2nd of September 2022

@Judy, If no one told you yet, leave it on! It will mess up the temp and humidity and the counter. It should only take a few minutes to candle because you want to do it quickly. Good luck!