The developing embryos have delicate blood vessels that rupture easily when severely jarred or shaken, thus killing the embryo.
Also as mentioned earlier, eggs are very vulnerable to vibration type injuries early in incubation. Shaking or jarring can kill the developing embryo either directly or by rupturing the yolk.
Hold an egg by your ear and shake it. If you hear nothing, then many say your egg is OK, based on anecdotal evidence. If you hear liquid sloshing around, it means the yolk and/or white have deteriorated and are no longer fresh and firm but rather old and watery.
The Sloshing Test
If you shake the egg and there's no sloshing noise from inside, it's fresh and can be eaten. If the egg makes a sloshing noise when you shake it, air has gotten into it and expanded the natural air bubble. Don't eat it.
“Blood spots” in raw eggs can lead to black spots in boiled eggs. Sometimes a chicken's egg-making machinery misfires and a bit of blood or a clump of brown protein winds up inside the egg. These stray bits, known as blood spots or meat spots, can certainly be off putting.
If you add the audio stimulation of a hen(s) clucking to incubating eggs you will have an increase in the hatch rate verses either eggs incubated in silence or eggs incubated with ambient noise.
Take the egg in your hand. Shake it a little. If you can hear a sloshing sound, chances are that the egg is rotten. If there is no sound, then the egg is fresh and ready to be used.
Shake it gently. If it's fresh, it won't make a sound. If it's on the older side, the egg will make a slight rattle. Peel: Fresher eggs are harder to peel which is why many people let their eggs age for a while in the refrigerator before making deviled eggs.
Take extra precautions when turning eggs during the first week of incubation. The developing embryos have delicate blood vessels that rupture easily when severely jarred or shaken, thus killing the embryo.
Through a process called osmosis, the vinegar moves through the egg's shell. The vinegar dissolves the calcium in the egg's shell but cannot get through the membrane in the shell. This leaves behind the rubbery membrane that allows you to bounce the egg without breaking it!
Bacteria will enter through the crack, and the support structure of the shell won't be able to keep the embryo in the correct position. Different aspects of the embryo could get damaged and leak out of the shell as well. It's very important that you act now if you want the chick to hatch properly.
Touching fertile, incubating eggs will not interfere with the hatching. The greatest risk you run is possibly disturbing the broody hen into abandoning the nest (not very likely for most hens) or introducing a bacteria that penetrates the eggshell, which is porous, that causes the embryo to die.
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.
Some women may notice symptoms as early as 5 DPO, although they won't know for certain that they are pregnant until much later. Early signs and symptoms include implantation bleeding or cramps, which can occur 5–6 days after the sperm fertilizes the egg. Other early symptoms include breast tenderness and mood changes.
It's important to watch out for signs that implantation has failed such as heavy bleeding, stomach pain, and a failure to locate a heartbeat during an ultrasound. There are many reasons why a fertilized egg may fail to implant, most of which are beyond your control.
Find out by candling
If the egg is fertile, then you should see a dark spot around the middle of the egg, with some spider-like veins beginning to form around it. If its not, you should just be able to see the shape of the yellow yolk inside the egg, without any signs of an embryo or veins.
Information. An egg can float in water when its air cell has enlarged sufficiently to keep it buoyant. This means the egg is old, but it may be perfectly safe to use. Crack the egg into a bowl and examine it for an off-odor or unusable appearance before deciding to use or discard it.
The growth of embryos and the hatchability of broiler chicks are not affected by prenatal auditory stimulation. Both MUSIC and NOISE at 90 dB, as measured by CPN, AGP, and CORT, are stressful to the embryos at certain developing stages.
Studies show that just as in humans, major abrupt changes to the day and night cycle of the chickens, such as waking up the chickens at night with loud noises, will lead to stressed and anxious chickens.
In addition, studies have shown that loud noises such as found near airports, rail road tracks or loud hydraulic or pneumatic equipment and machinery close to the chickens leads to lower egg production, stunted growth, higher blood pressure, stress and fatigue in the chickens.
A fresh egg should have a bright yellow or orange yolk and a thickish white that doesn't spread too far. If it's off, the yolk will be flatter and discoloured and the egg white will be far runnier. As we've already described, rotten eggs will also have a sulfuric smell to them.
Black or green spots inside the egg may be the result of bacterial or fungal contamination of the egg. If you come across an egg with black or green spots discard the egg. Off color egg whites, such as green or iridescent colors may be from spoilage due to bacteria.