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Breeding Your Own Chicks
Humidity
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Introduction Breeding Stock Suitable Eggs Incubator Egg Turning Temperature Humidity Candling Pipping & Hatching Optimum Conditions Useful Items |
Another factor that is crucial during the process of incubation is the level of humidity or amount of water vapour in the air. For the first 19 days it needs to be at 55% for hens’ eggs, but from the pipping stage onwards should be increased to 75%.
The first allows sufficient air in the air cell to be available to the growing chick. If humidity is too high at this stage, insufficient water is being lost from the egg and the air cell is too small to allow sufficient oxygen. The embryos die, a condition usually referred to as ‘dead in shell’. If humidity is too low, the egg membranes dry up so that the chick is unable to break out of the shell.
Candling the eggs (see later) allows the size of the air cell to be checked. If it is too small, the humidity is too high and should be reduced. If too large, too much water is being lost and the humidity needs to be increased.
Many incubators have water trays or containers to provide the necessary humidity, with instructions on when to add extra water. It is obviously vital to follow the instructions for individual incubators, as they will vary from one manufacturer to the other.
Some machines have a humidity gauge, but if not, it is easy to buy one at a DIY store. I have a light plastic one that is suspended just above the eggs. Having too high a humidity level is usually more of a problem in our damp climate, hence the recommendation made earlier, to place the incubator in a warm place inside the house. Some large breeders use dehumidifiers to reduce the humidity level. These are now available for small incubators as well as large ones.
Copyright © Katie Thear 2005