From natural brooding to artificial incubation

From natural brooding to artificial incubation

In natural conditions, a hen incubates five to ten eggs, but in a commercial hatchery we are talking about tens of thousands. The entire incubation process aims to mimic the natural process, but because of its scale, specific demands and requirements are involved. To understand artificial incubation, it helps to understand how eggs are incubated - or brooded- naturally. Each incubator is unique, creates variation, and therefore has its own specific incubation program. The average eggshell temperature and the variation in eggshell temperature are the most important factors (not the incubator set point temperature). The hatchery manager has to identify the specific characteristics of each batch of eggs and know the features of the incubator. The breeding organisation and the incubator manufacturer provide manuals that describe the most essential basic operations/settings for eggs and machines.

Natural

Egg collection Incubator

The hen lays a clutch of about 10 eggs. The hen only starts brooding her eggs when she has laid enough. In the meanwhile, she regularly sits on the eggs to warm them up.

The temperature of the egg storage room is low (15-18°C), but can sometimes be increased intentionally for a short period (SPIDES: Short Periods of Incubation During Egg Storage). This takes place in a special SPIDES room or incubator.

Keeping the hatching eggs warm

The broody hen will not leave the nest for the first six days. She sits nestling her chest onto the eggs. The body temperature of the hen is 41°C (106°F). The incubation temperature is slightly lower: 37.8°C (100°F).

copyright protected The most important thing is keeping all the eggs warm at the same temperature. Ventilating with fresh air is reduced to an absolute minimum, to ensure the temperature of all the eggs is as uniform as possible.

Turning the eggs

The eggs never lay completely horizontal. They are tilted with the point downwards at an angle of at least 20°. As the air cell increases in size, the eggs naturally tilt during incubation with the larger rounded end facing upwards. This ensures the chick is positioned correctly near the air cell. In trays, the eggs should be positioned with the point downwards during storage. In the setter, the eggs should tilt at 38-45°. The setter trays are turned every hour (so in total 76-90°).

Natural Incubator

Turning the eggs

When incubating her eggs, the hen turns them several times a day. She also swaps the positions of the eggs around regularly so they all receive the same amount of heat. Eggs are turned automatically with a turning device.

Cooling the egg

As the incubation process progresses, the hen regularly leaves the nest so the eggs cool and come into contact with fresh air. The hen sits less firmly on the eggs.

Removing heat and gas exchange gain importance in the second part of the incubation process. The chicks hatch copyright protected After 21 days of incubation, the chick pierces the eggshell with its egg tooth. Because most of the calcium in the eggshell has been used to form bones and feathers, the eggshell is now soft enough to be broken. In the hatcher, the chick emerges from the shell and rests after all its strenuous effort. In some hatchers, the chicks have immediate access to feed and/or water.

Post-hatch

The chicks sit under the hen’s wings and do not eat until all the eggs have hatched and the hen starts to walk around. If they are not too cold or too hot, chicks can stay in the hatcher for a while, or be transported, without feed and water. Energy is stored in body tissues. The yolk sac provides additional feed and moisture during the first few days.