Hobbies And Interests
Purpose
Candling increases the chances of detecting healthy eggs and discarding infertile or bad eggs. It helps detect abnormalities, such as bloody whites, blood spots, meat spots and cracked eggshells. It does not harm the embryo unless you heat the egg up too much. If the egg appears clear or reveals cracks in the eggshell, you can discard it. Typically, the embryo appears as a dark shadow with the head as a dark spot when viewed under a candling light. Healthy embryos respond to light and show movement. If the movement is slow and takes around 30 to 40 seconds, discard the egg, as the developing embryo is unhealthy.
Pay attention to the blood vessels. Unlike a healthy embryo, in unhealthy embryos the blood vessels are not well defined but appear as streaks under the shell. You will notice a small dark area with degenerating blood vessels in case of early deaths. This may appear as a dark ring around the egg. Late deaths and viable embryos at the same growth stage look similar except for the absence of movement and deteriorated blood vessels.
Mark the air sac and the inoculation site before you place the eggs in the incubator for inoculation. Discard the infertile or bad eggs, as they may explode in the incubator and contaminate other eggs.
Making Your Own Candling Lamp
Place a very bright bulb that does not generate as much heat as a conventional bulb and light fixture inside a cardboard box. Cut a small round hole on top of the box. The hole should be just big enough to sit the pointed end of an egg. Place the egg in a slanting position on the hole, and illuminate the bulb. The inside of the egg gets visible once the light penetrates the shell. You can now identify the fertile eggs from the infertile ones. Place the candler on a table or box at a height of 38 to 44 inches from the ground to avoid light shining directly into your eyes.
Candling Brown or Dark-Shelled Eggs
White eggs are easier to candle than brown eggs because of their color. Get the brightest possible source of light to help you see through the dark-shelled egg. Usually, you may have to wait a little longer to see the embryo compared to a white-shelled egg.
Candling Artificially Incubated Eggs
Artificially incubated eggs are candled to determine their viability and track the growth and development of the embryo. Test the white eggs on the third day for fertility and the brown-shelled eggs on the sixth day so it is easier to see the embryo. However, it is best to test the eggs after the first week, as this is the most critical phase of incubation and gives more assurance about the fertility. Frequently perform candling to observe the growth and development of the embryo. Remember to candle eggs during the early stages of incubation, otherwise you will not be able to distinguish between the various stages of the egg.