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Candling and Transfer
Establishing true fertility in hatching eggs
- Written by Marleen Boerjan
If it comes to discussions on fertility two different definitions are practiced. A true fertile egg contains a well developed germinal disc (blastoderm), which indicates that the oöcyte, or zygote, was fertilized and an embryo developed during egg formation. Secondly, in the practice of the hatchery fertility is often based on candling, whereby all clear eggs are defined as unfertile and by default the rest of the eggs are considered to be fertile. This second definition of fertility is strictly not correct since clear eggs may contain both truly infertile or they may contain (fertile) embryos that died early.
When and how to transfer eggs to the hatcher
- Written by Gerd de Lange
Traditionally, setting and hatching occurred in the same incubator, with new eggs being set twice weekly. Generally, hatching baskets were situated at the bottom of the incubator, where temperatures were lower. But this system was not successful in terms of maintaining egg hygiene, as the fluff from hatched chicks contaminates unhatched eggs, and the system did not facilitate proper cleaning and disinfection. It was also impossible to create optimal climatic conditions for eggs of various setting dates and the newly emerging chicks at the same time.
To candle or not to candle, that’s the question...
- Written by Gerd de Lange
During the incubation process, eggs are candled to determine the number of infertile eggs and eggs with dead embryos, together indicated as ‘clears’. This can be done as early as day 5 - 6 of incubation by an individual candling light, but it is time consuming - and the risk of candling errors (e.g. accidentally removal of an egg with a normal living embryo) is evident.
Read more: To candle or not to candle, that’s the question...
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