CHAPTER 7:
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Setting
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Eggs with the same origin and production characteristics are placed in setter trays after being gradually warmed up in a setter room or incubator. The embryo in a hatching egg is a living being that develops,
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py
in stages, from a single cell stage into a fully-fledged chick. Keep this in mind at all times.
You need to know the following before setting each batch of eggs:
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The quality of the hatching eggs (eggshell quality, age, parent stock, results of the previous batch set, storage time)
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Incubation conditions (program: temperature, relative humidity, ventilation, turning)
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Developments in the hatching egg (% fertile, early embryonic mortality)
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Assessment of the previous hatchability (% hatched and chick quality)
During the first 10–12 days, the temperature has a particularly important effect on embryonic growth and development. After that period, the embryo adapts tentatively to the microclimate. From the sixteenth day, the embryo reacts to excessively high or low temperatures by increasing or decreasing its heart rate. With a higher heart rate, more heat is transferred to the eggshell, while the embryo retains its metabolic heat at a lower rate. However, embryos only have very limited capacity for temperature regulation. This is mainly dependent on environmental conditions. An embryo can survive well for a few hours with a lower ambient temperature (25-28°C). A longer period with an excessively high temperature (> 39°C) has a negative effect on embryo development, and on the heart in particular.
Ha tc he ry S i gnal s
