Topic of the Week - Candling Eggs


Staff member
Premium member
8 Years
Jun 28, 2011
Tipperary, Ireland

Pic by @WVduckchick
Many of us incubate eggs and some point start candling the eggs to check for fertility, development, air cell growth etc. This week, especially for those new to incubating and candling I would like to hear you all's tips and tricks when it comes to candling eggs. Specifically:

- What do you use to candle eggs?
- What about candling dark shelled eggs?
- When do you start candling eggs?
- What do you look for when candling and what are the signs you need to give up on an egg? (I.e. what is normal, what are the warning signs, etc)

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Jul 10, 2017
Rechasim, Israel
- What do you use to candle eggs?
A high powered LED flashlight
I have seen incubators that have an individual LED light under each egg in the turning tray. Personally my incubators don't have it, but it is a cool idea.

- What about candling dark shelled eggs?

Using the high powered flashlight most dark eggs can still be candled albeit not as clearly.

- When do you start candling eggs?
Not before day 3 are up (72 hours after setting the eggs)

- What do you look for when candling and what are the signs you need to give up on an egg? (I.e. what is normal, what are the warning signs, etc)
The first time (after 72 hours have passed since setting) I candle just to determine the fertility of the eggs. Despite having very sexually active roosters, not all eggs are fertile. Some may just not be fertile while others may have been stored for too long, damaged in transit ect. If there are no "spider-web" blood vessels at this stage the eggs can be discarded.
The second time is on day 14. At this stage the point of candling is to make sure there are no rotten eggs that can explode and contaminate the other eggs. If an egg has swirly liquid inside which will spill into the air pocket when overturned, get rid of it. Just a word of warning, do not open the egg, the stench is overpowering.

I do not keep track of the air pocket size.


Free Ranging
Mar 16, 2018
Bay Area, California
My Coop
My Coop
- What do you use to candle eggs?
Magicfly plug in flashlight.
See pictures below.

- What about candling dark shelled eggs?
Same thing. Just harder to see. I look for "darker shades" rather than embryos and legs and all that.
- When do you start candling eggs?
When i get the egg i candle to see what the air cell looks like (if visible)
Then i candle every day!
Generally i think the day 4,11,18 method is fine, i just like to watch growth and see variances. Three incubations under my belt and i still don't know squat.

- What do you look for when candling
Go look at people's photos of candled eggs (preferrably where the day is marked) and see what soon-to-be chickens look like. If your eggs look similar during candling, you're doing good! If not, your normal like the rest of us! Keep watching and cross your fingers, and take some notes. You'll have to create your own method. And then things will still go wrong!

and what are the signs you need to give up on an egg? (I.e. what is normal, what are the warning signs, etc)
Never give up, never surrender!
On a more serious note, it all starts on day one right? In a lighter egg, you can often see daily changes over the first week. And the darker ones go from "is that the yoke?" To "ah, there's a darker spot!" By day 4. I'd suggest tossing infertile around day 4...but if you want to wait until 7 be my guest. Longer than that would make me nervous, but I've never seen an egg blow up first hand, so you do you.
On my second incubation, we had two fail to launch, one quit around day 5, one quit around day 12, and one quit at day 19. (BCM eggs). It only took a couple of days to see a noticeable mass difference in the eggs, but we left them in anyway until the last successful hatch.
My advice, toss them as soon as you know they are a dud. That being said, i realize giving up on any chicken is a controversial subject and so any chicken incubating person should realize that it's up to them, and "knowing" probably only works for the professionals. As mentioned, I'm still trying to figure it out.
Last but not least, recognize that the reason folks discuss "success rates" is because they *often* have failures. In three sets of nine eggs in a janoel 12, SavKel and i have had 3 fail to launch, 4 fail to hatch, and 5 that needed post hatching treatment (unabsorbed yolk, webbed toes, and curled/straddled feet) our second incubation came from Craigslist and only had 1 healthy chick out of the lot. We believe the issue was due to a high humidity, but could have been a combination of things.
Best of luck to whoever starts incubating after reading this thread!
And of course... Pictures!
20180312_181145.jpg 20180422_205211_Film2.jpg 20180422_205147_Film2.jpg 20180422_205200_Film2.jpg 20180422_205408_Film2.jpg 20180422_205243_Film2.jpg 20180422_205259_Film2.jpg 20180424_201608_Film2.jpg 20180425_201143_Film2.jpg 20180425_201801_Film2.jpg 20180427_075141_Film2.jpg 20180427_231057_Film2.jpg 20180428_201144.jpg


For The Birds!
Premium member
Feb 9, 2015
West Virginia
My Coop
My Coop
Wow, @sumi thanks for using my candling pic for this TOW!

That picture was taken in my Nurture Right incubator. I love how easy it is to candle through the window without having to open the incubator.

What do you use to candle eggs?
I use a MiniMag Maglite, with some thin craft foam wrapped around it with a small round hole cut in it. I think its 425 lumens. Fresh batteries are also of utmost importance!

- What about candling dark shelled eggs?
The brighter the light, the better for dark shells. And candling in a dark space. I've only done really dark shells a couple of times, I could still see the air cell and enough dark blob and occasional blood vessel to tell if they were growing or not.
Surprisingly, my lavender orpingtons laid a very light pink colored shell, but they were still very dense, and difficult to candle until at least day 10.

- When do you start candling eggs?

I was addicted to candling when I first started incubating. I would candle almost daily, starting around day 3-4. I don't always handle the eggs, but usually candle them in place, as they are in the incubator. I find myself candling less and less, the more I incubate now though.

- What do you look for when candling and what are the signs you need to give up on an egg? (I.e. what is normal, what are the warning signs, etc)

I look for nice red blood vessels in a spidery web looking network, full CAM development, and movement of the embryo inside the egg. Lack of these things would be warning signs that one has stopped developing. Blood rings or solid blobs would also be warning signs. Huge "clear" area where there are no blood vessels would also cause me concern.
Air cells - should be attached firmly to the inside wall of the egg and be uniform shape. (shipped eggs are a total different ballgame, with additional warning signs, etc)

A few of my favorite candling pics.
Polish egg

Quail egg

Black Swedish duck egg

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