Critical embryonic stages Period
Point for attention
Differentiation: different organs develop.
In the hen, first week in setter.
Avoid cold spots for a narrow hatch window.
Growth: exponential increase metabolism.
Second week in setter.
Be aware: risk of overheating. Start ventilation to sustain the oxygen requirement.
Maturation: physiological control circuits mature.
Second half setter + hatcher + first week at the farm.
The right temperature to control development of body temperature. All organs mature best when incubated at the optimal temperature. Any deviation from optimal delays developmental stage at hatching.
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Phase
There are three phases of embryonic development. During incubation, the climate conditions must be just right to support each embryonic stage.
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In most incubators, it is unwise to mix eggs with different origin and production characteristics because each type of egg requires different incubator settings. If you mix eggs, it is impossible to maintain the incubation conditions at the optimal levels for all the eggs. This applies less with incubators with sectional control. If mixing is necessary, stick to this order of importance: 1. Origin (incl. vaccination schedule) 2. Parent stock age 3. Fertilisation rate (based on history) 4. Storage duration A few days difference in the storage period is less important than a couple of weeks difference in the ages of the parent stock. Note: the laying date determines the planning of the hatchery, not the day the eggs arrived at the hatchery. Some incubator manufacturers supply a help program, showing how to fill the unit (the positions for each trolley), based on the expected heat production of the egg mass.
pr ot
Do not mix
Development of membranes and chambers
allantois amnion
yolk sac
embryo
air cell
amniotic cavity
eggshell
Eggs from the same flock are coded with the same colour, so you can see, at a glance, which eggs are in which machine. Here you can see that eggs have been mixed.
7. S et t i n g
chorion
yolk
albumen
This embryo is 8-10 days old. The foundation for development of all the organs is laid during this stage. There are four components of extra-embryonic tissues and compartments in the egg: 1. The amniotic cavity: protects against impact and dehydration 2. Blood vessels and yolk: nutrition 3. Outer membrane with the allantois: gas exchange 4. Inner membrane (amnion) surrounding the embryo: protects, supports embryo movements, delivery of maternal antibodies (immunoglobulins), and the allantois (storage of metabolic wastes, e.g., urates).
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