Information on Candling Eggs

By BantyChooks · Nov 3, 2017 ·
  1. BantyChooks
    This is a work in progress, please be patient.

    How to Candle Eggs

    There are two different ways to effectively candle eggs. One pertains to shipped eggs with air cell damage and the other to non-shipped eggs.

    Shipped Eggs:
    Always keep the eggs air cell end up. It's best to leave them in an egg carton if you can. Put the light source on the air cell, not the bottom end or you will be able to see very little. Do not turn or rotate the egg, move the flashlight around it. This goes for other candler types too, even the stand candlers like the Brinsea OvaView. Flip the candler, not the egg. Don't jiggle or slosh the egg, that can kill the embryo.

    Image set one: how to hold the flashlight/other light source to candle eggs in a tray, i.e shipped.
    candle1.jpg candle3.jpeg candle4.jpeg

    Non-Shipped Eggs:
    Hold the egg at a slight angle, large end to the light source. Make sure your fingers don’t block the light and turn the egg slowly until either you see something or you’re certain there’s nothing to see. Again, be careful with the egg, but you can move it around much more than you could with a damaged one.

    Image set two: how to hold the flashlight/other light source to candle eggs that can be rotated. The dotted line in the second image is showing where the air cell is.
    candle2.jpeg candle5.jpeg

    When Not to Candle
    Text credit goes to @MyPetChicken .
    Egg candling can be a most addictive experience. Years ago, when I first started home incubation, egg candling would begin on the third day, and then happened again nearly every day thereafter until lockdown. I couldn’t get enough. Secluded in a dark room with a very strong flashlight, I would imagine my pile of eggs developing and hatching into the most beautiful flock that would ever grace my part of the county. Witnessing the embryo jump and move through the shell during egg candling was almost as exciting as watching my own baby on the ultrasound machine when I was pregnant. My imagination would not cease until the babies finally hatched and were moved into their brooder… where yet another addiction would take over—chick watching—but that’s another story. THIS story is about the problems that arose for me when egg candling was done too often.

    Here are five reasons why egg candling too often has caused problems for me:

    1. I discarded viable eggs.
    I’ve learned that there is really no reason for me to candle an egg prior to the 10th day. If egg candling happens any sooner than that, I might toss an egg that is growing just fine. If you’ve ever had that sickening feeling in the pit of your stomach after opening a “cull” egg just to find a beautiful little chick growing, then you’ll know where I’m coming from. I also candle a bunch of dark-shelled eggs. When egg candling it is wayyyy easy to miss a growing baby behind those mahogany shells. WHEN IN DOUBT, leave it in the ‘bator!

    2. I detached fragile air cells.
    Shipped eggs bring their own set of rules. Thousands of dollars and many eggs later, I’ve learned a few things… one of which is that I have far better results if egg candling doesn’t happen right after they’ve been taken out of the box and unwrapped.
    Now I simply give them a good visual inspection and allow them to rest. Resting means allowing the eggs to sit in the incubator for a few days, big end up, without the egg turner on. When egg candling happened too early, the extra handling, no matter how gentle I tried to be, often disturbed the fragile air cell. Now I just leave the darn things alone! You may think think that’s crazy talk, because conventional wisdom suggests egg candling right away to make sure there are no hairline cracks in the shells that can’t be seen by the naked eye. All I can say is that leaving them alone rather than egg candling that early has increased my shipped egg hatch rate by quite a bit.

    3. I contaminated my eggs.
    It is always imperative to only handle your hatching eggs with very clean hands. Over-handling, e.g. over-candling, will increase the potential of an egg getting contaminated from dirty hands, a sneeze or anything else! Contaminated egg shells create dead chicks or an egg that could explode in the incubator! Which brings me to this: Even if you smell a bad egg, it is not necessary to candle. VERY carefully put each egg to your nose and take a whiff. You will smell a bad egg quite distinctly, and you can remove it from your hatch without having to candle.

    4. I dropped fertile eggs.
    It is always a sad day when I drop an egg, even if it’s just headed for the frying pan. Imagine how much more tragic it is when the egg is destined for hatching. But it gets worse: you can also drop and egg being candled onto the eggs below it! Talk about a dingbat moment, you should have seen me the day I decimated three eggs that were growing beautifully just because I dropped one during a sneeze (see Rule #3). I couldn’t have cried more if my dog died!

    5. I lost heat and humidity in my incubator.
    Back when I used a homemade and styrofoam incubator, it was always a very worrisome headache trying to keep the humidity and temperature just right. There were nights I would spend on the floor next to the eggs to try to regulate the heat properly in an uncooperative incubator that became unruly every time I had to open the lid to turn, much less candle. Adding an egg turner to your incubator, and candling less often, will reduce the number of times you’ll have to fight this battle. (Bonus tip: Adding a little aquatic tubing so you can easily fill the water reserves will alleviate another reason to open the lid as well.)

    Those are the five reasons I’ve reduced my egg candling.
    So when DO I candle? Only twice, once at 10 days and again at 18 days. I candle at 10 days to cull the clears and the obvious quitters, and I can also perform the “sniff test” to detect if any are bad or rotten. Then I candle again at 18 days to cull any other quitters or bad eggs I might detect prior to lockdown. The next time I handle the eggs is when nothing can be hurt: during clean up, after the babies have hatched.
    Many people may disagree and candle more often, but I can only speak about what works for me. Now, I physically cringe when I read, “I’m on day three. I keep candling but I can’t tell if these eggs are fertile.” Yikes! Granted, that used to be me, but having hatched literally thousands of chicks at this point, I’m hoping that someone out there will read this post and learn from my egg candling mistakes so they can take advantage of my experience to improve their hatch rates!

    End of text from MyPetChicken.

    Candler Suggestions

    PowerLux Egg Candler
    Product No. EC116 36.95
    Hand held candler w/ a long lasting LED light. Use on white or brown shelled eggs to candle general embryo development. Comes with two easy to change end pieces for large and small eggs. Cord length 8 ft. Looks like it works well
    #237 #33879

    Sally's Candler
    1" foam pipe to LED light #1645

    After hatching so many marans, I needed a good one! It's 3000 lumens. I researched to find the brightest I could get in the most handy as well as cheap! I have bought up to 1500 lums and couldn't see into dark blue eggs, now they look like I am candling a duck egg, very quick fast and done. Love it!
    Well worth the money spent and the rechargeable batteries rock!
    Mic Stand — eBay (link might break) and another source

    Saris' Candler
    Modified toilet paper tube attached to a flashlight #49

    Chicknlove's Candler
    Light sabre candler! #40823

    Peachickie's Candler Find
    APG 3000 Lumens Zoomable CREE XM-L Q5 LED Flashlight Torch Zoom Lamp Light - 3 Mode Adjustable Brightness Waterproof Design Torch Lighting for Hiking, Camping & Outdoor Activity (Black) Click Here
    • Skid-proof, waterproofing design, "O" ring sealed.
    • Super bright, blinding effect, adjustable focus range for different usage.
    • Convex lens reflector; clip for convenience carry.
    • Internal wiring applies the high efficient booster circuit, working voltage is wide and can utilize the batteries in the largest extent.
    • Suitable for self safety, hunting, cycling, climbing, camping and outdoor activity etc.
    Ozexpat's Candler
    Click Here

    PrizePete's Candler
    Click Here #33920

    Joey's Candler
    Click Here

    Fire370's Candler Suggestions

    BYC910's Candler

    Alkaline Battery Recharger for AAA, AA, C and D size Batteries
    About the Product
    • total of 4 charging stations
    • 4 AAA or AA batteries, 2 C or D batteries or 2 AAA or AA and 1 C or D batteries at one time
    • Help benefit the environment and save money on replacement batteries.
    • Charges brands such as; Duracell, Eveready, Sanyo, Polaroid, Panasonic, and Rayovac
    • With the cost of a typical alkaline battery 6 pack ranging in price from $4.99 to $8.99, this unit will pay for itself in just a few re-charges.
    Click Here

    S5's Candler


    Flocktastic's Candler

    Mamahmendez's Candler

    Stromberg's Candlers
    Click Here

    Cynthia's Candler
    I know I don't explain things the best, here is a I said, have been using this for yrs. And yes, that tape is fine, gets a bit warm if I take a long time candling, say..30 eggs. Never been a problem overheating though. Cynthia12
    LL (2).jpg LL (3).jpg LL (4).jpg
    I just clip it on the bottom drawer when I want to candle.

    Try more than one flashlight for dark eggs!

    If you have a cell phone you can use a flashlight app to candle. It works quite well.
    LL (5).jpg

    Clears at Candle are not Always Infertile

    Always break open clears before passing a verdict on fertility rates, especially if the eggs are shipped. Early deads are easily mistaken for clears when candled and sometimes they will be fertile but fail to start. Read the links below for more information on identifying early deaths, infertile eggs, and FND eggs.
    Article One
    Article Two
    Assessing Fertility After Incubation? #686

    Links on assessing fertility: Click Here [add later when fertility section complete]

    Sharpies on Eggs? Sure!

    It's a question nearly as old as the proverbial which came first: can you safely use sharpies on hatching eggs to mark air cells or identify breed? Some BYCers have decided to take this to the extreme and colour the entire egg with multiple colours of Sharpie. Results are quite strongly indicative that it has no effect on hatchability.
    Kathy's Sharpie Eggs #57059
    Lamancha's Sharpie Eggs #8782
    ILOVEFRIZZLES' Sharpie Eggs #1
    From #57461

    Saddle Shaped and Rolling Air Cell Images

    Saddle shaped air cells are when one or both sides of the egg have a large dip in the air cell. A lot of times with saddle shaped cells the chick doesn't position correctly for hatching. Their feet can get stuck behind their head and "smoosh" the chick so it can't move. It can also force the yolk sack and everything else more north in the shell. Keep a close eye on these eggs and make sure to pencil mark air cell lines. They are very common in shipped eggs. Please see the rest of the notes section for information on turning these eggs correctly.

    Saddled air cell in early dead SH

    Saddled air cell in early dead SH

    Saddled air cell in early dead SH

    g.png LL (1).jpg

    Rolling air cells are just what the name implies: bubbles of air that roll freely throughout the whole egg like a carpenter's level. Prognosis for these eggs is generally poor and sometimes they are scrambled also.
    index.jpeg LL (1).png

    Development of a Chicken Egg Day by Day
    Candling Pictures day-by-day Click HERE

    Bubble in Egg that's not from Air Cell? #25651
    Blood Rings #25422 #43578 #80777
    DIS Eggs #80780
    Candle of Eggs with Incomplete CAMs #80783 NOTE edit later w/more info
    Candle of a Fresh Egg #80804
    Frozen and Re-thawed Egg #40744
    Seeing development 12 hours in? Yes, it's possible! #29561
    Miscellaneous Neat Candles #32316
    Coturnix Quail Candling Guide

    Are my Air Cells the Correct Size? See Below.
    candlea.jpeg candleb.jpeg candlec.jpeg

    Candling Images:
    *Note---unless specified, all images are of chicken eggs*
    Day 18+ candles for chickens are in the lockdown section below.

    For more poultry information and notes please CLICK HERE for the Complete Guide to Incubation, Poultry Raising, Care and much more!

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