Eggs may be candled after 5 days of incubation and every few days thereafter. For best results you should candle eggs in a darkened room or in dimly lit conditions. The candler should be held right against the shell at the larger end of the egg where the air sac is located.
I recommend candling chicken and duck eggs after 7 days of incubation and again at 14 days. After a week of incubation, you can be reasonably precise about the viability of the embryo. At 14 days, you can remove any eggs with embryos that have died and lessen the risk of a rotten egg exploding.
Did you know you can determine if an egg is fertile or not by looking at the germ spot? The germ spot is the white spot on the yolk. The non-fertile germ spot contains only the female's cells and looks like a solid white spot. In a fertile egg the germ spot contains both the female and male cells.
Healthy embryos will respond to the light by moving. Sometimes the movement is very sluggish and it can take 30 to 40 seconds for the embryo to move when held under the candling lamp. This indicates the embryo is not healthy and the egg should be discarded.
You will need a bright light to look at your eggs, and your room will need to be dark. Poultry supply or farm supply stores sell egg candling devices, but you can also make your own. Take a 60 watt light bulb and a coffee can. Make a hole with a one-inch diameter in the top.
You can use either a small, basic flashlight or an expensive, high-end machine to do your candling. It's important that you do not candle every day so as to not disturb the growth and development. Also, avoid using eggs that are dirty or soiled in any way.
Infertile Egg: An egg that is not fertile will remain clear. If you look closely, you can see the yolk in the middle. Blood Ring: If a developing embryo dies, the blood vessels form a blood ring. It can be located in different places within the egg.
By being able to identify and remove non-viable eggs (infertile or early death) you can also avoid the risk of a rotten egg exploding and contaminating your hatch with dangerous germs. And candling does not harm your eggs.
Day 15. What is this? You can see here how the embryo is now filling a large part of the egg. Candling at this point provides a view of the vein - just above the air cell - moving quite energetically as the chick positions itself for hatching.
Candling is when you shine a bright light through an egg to illuminate its contents. It gives you a good idea of an embryo's development. Don't candle eggs after Day 17 as any movement can harm the chick.
It is best to incubate eggs within 7 to 10 days of their being laid. Hatchability decreases rapidly when eggs are stored for more than 10 days. After 7 days, hatchability decreases 0.5 to 1.5 percent per day. Each day in storage adds one hour to the incubation time.
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!
When candling eggs, inspectors look at the blunt end to measure the air space. In a very fresh egg, it will be very small, roughly the size of a dime, and as the egg ages the space grows larger. It should also be fixed and not free-floating or ruptured.
Sometimes eggs found outside the nest are viable and sometimes she continues to sit on rotten eggs until the bitter end. I wish I had a nickel for every rotten egg I have discovered in the nest after a hen has left it to care for her brood.
Hatching chicken eggs: days 1, 2 and 3.
Initially the egg will look clear, apart from the air cell which you may be able see at the 'fat' end of the egg – but probably not before day 4 or 5. As time goes by you'll notice this air sack become larger.
If chick embryos develop to the pipping stage, or at first shell cracking at hatching, they are normally healthy enough to hatch unless some incubator adjustment prevents it from happening. The problem is usually caused by either 1) poor ventilation or 2) improper humidity.
Bad Eggs A red ring around the egg indicates embryo death and the egg should be removed from the incubator immediately. Always wash hands before candling to avoid contamination. I always SMELL the eggs when candling for signs that the egg has died from bacterial contamination.
When should incubator lockdown take place? The optimum time is three days before the eggs are due to hatch. For normal sized chicken eggs this is at Day 18 of incubation.
You might be surprised to find that candling on day 10 is more difficult than on day 4. The reason for that is that the embryo has grown so much since you last checked it that less of the egg around it is visible.
* You can candle your eggs every day if you'd like, after day 3 you should see something. * Be sure your hands are clean and dry. Oil from your fingers can clog the pores in the egg shell and keep the embryo from getting the oxygen it needs. * At about 8 days, you can see the peep wiggling and kicking in his egg.
Embryos need considerable moisture to hatch properly and easily. High humidity tends to produce a late hatch; low humidity an early hatch. Do not turn the eggs the last three days of incubation. The embryos are moving into hatching position and do not need to be turned.