Candling
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So, the timing of candling depends primarily on the goal. The blood ring stage is one example of a critical moment in the incubation process. If something has gone wrong in the breeder house, in storage, or during transport, you often see the effect reflected in increased mortality on day 3. If eggs with dead embryos have been in the incubator for a prolonged period, it is increasingly difficult to pinpoint the precise time of death. Candling during the process creates more moments to provide feedback to the breeder farm. It also helps you identify the moment a problem starts more accurately. If you only candle on day 18, and you include the storage duration in your calculations, you are already 3 weeks too late to make any changes in breeder flock management.
Caution!
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Candling allows you to see which eggs are infertile, contain dead embryos, or are viable. For example, you can carry out candling with a breakout analysis, at four fixed ages in each parent stock flock (in each house). This will generate a lot of valuable management data, which can help breeder farms and hatcheries. But you must analyse and use this data to create your own hatchery specific reference data. This will give you insight into all the details: the breed, feed used, nest type, feeding system, lighting, ventilation in relation to fertility, hatchability percentage, and chick quality. So, you have a wealth of information! • Candling on day 2 is mainly used to determine the rate of fertilisation, e.g. in young flocks. • Candling on day 10 is not standard practice, and it primarily provides a picture of early embryo mortality. It might be used more often in the future if in-ovo sexing gains in popularity as a practice in the layer production sector. In this case, you would only transfer pullets, and would be able to remove infertile eggs and dead embryos immediately. • Candling on day 18 is the most practical method because it allows you to remove infertile eggs, eggs that contain dead embryos, and, above all, rotten eggs, so the chicks that hatch will not be contaminated. However the data gained from candling at this time can no longer be used to influence the process.
Clear eggs are not all infertile. You need to breakout an egg to determine whether it is infertile or an early embryonic mortality.
Maintain a constant temperature Ensure the ambient temperature is at least 25°C/77°F during candling. If you want to put the eggs back into the incubator, make sure the handling time for candling does not exceed 30 minutes per trolley.
Breakout image at 2 days
Good hatching egg, fertile
Infertile egg
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You can recognise a good hatching egg by the round, doughnut-shaped embryo. You see a white, symmetrical ring (area opaca) with a clear core (area pellucida). Sometimes, you see a little white point in the centre. This is larger than it is in an infertile egg. 112
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You recognise an infertile egg by the imperfectly round shape of the embryo, with a jagged edge. Usually, multiple bubbles joined together. You see a little, compact, white point, sometimes slightly grainy.
X Fertile: the germinal disc always has a rounded, doughnut shape and a white symmetrical ring with a clear centre point, sometimes with the white dot in the middle. Infertile: the germinal disc is almost never perfectly round, has a jagged edge, and a very tiny white point. Ha tc he ry S i gnal s
