The environment of the egg

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The environment of the egg

In natural conditions, the hen provides an optimal incubation environment for embryonic development. During an artificial incubation process, an individual hatching egg has precisely the same needs. The most important factors are turning the eggs, and the ambient climate around them: temperature, CO2/O2 concentration, and (relative) humidity. These climate factors are closely interrelated, so making the right management decisions is important. The climate is continuously measured and adjusted. Each phase of incubation requires specific settings depending on the type of eggs. These settings may vary according to the type of incubator. The settings must factor in fertilisation and the number of live embryos. There are also other factors that can directly or indirectly influence the heat production of the embryos, such as the age of the embryos, egg weight, type, eggshell quality and the availability of oxygen. The embryo temperature is the result of the balance between heat production and heat loss. Heat loss mainly occurs because all eggs lose 0.6-0.7% of the initial weight of water per day through evaporation on the eggshell and the movement of air over the eggs. Preventing large fluctuations in the climate is essential. The embryos will develop optimally during the first 18-19 days with an embryo temperature of 37.8°C (100°F). After pipping, the embryo temperature may increase. The optimal embryo temperature on day 20-21 of the incubation process gradually increases to 39.0-39.5°C (102-103°F). A broody hen never leaves the nest? People often think that a broody hen never leaves her nest. That is certainly true for the first few days, but as the incubation process progresses, she will occasionally leave the nest to eat and drink. This allows fresh air to reach the eggs and moisture to evaporate. An incubator mimics this behaviour by the temperature settings in the program. In nature there is also a temperature gradient (the hen’s breast is warm and gets colder towards the floor). In an incubator the temperature is the same all around the egg. The four pillars of incubationcopyright protected

1. Temperature:

the embryo requires a constant temperature for its development.

This means introducing heat at first, then removing heat at a later stage.

2. Turning:

essential for the first seven days.

Turning the eggs stimulates embryonic growth and prevents the embryo from sticking to the inner shell membrane.

embryo age egg and yolk weight type (layer/broiler) shell quality oxygen supply machine temperature

3. Relative humidity:

moisture loss/weight loss of eggs.

4. Gas exchange/ventilation:

supply of O2; removal of

CO2/H2O and heat. Factors that determine the heat production of embryos.