After a certain period of storing hatching eggs, the hatch of fertiles will go down. We want to reduce this loss of hatchability as much as possible. The loss of hatchability during storage depends on the breed, time eggs are stored and the temperature and humidity during storage.
Time
On the average, the hatch of fertiles will go down after approximately 7 days of storage. Older flocks are more senstive for storage. When flocks are older then 45-50 weeks, the hatchability might go down already after 4-5 days of storage, while young flocks (younger then 35-40 weeks, can be stored for as long as 9 days without negative effects. Not all breeds are equally sensitive for storage. Why that difference occurs is not known.
Temperature
The optimum storage temperature depends on the storage time. Storage temperature must be reduced when storage time incrases. In general, the following scheme can be used:
Storage for: storage temperature:
2-4 days 20 - 22 oC
4-7 days 17 - 19 oC
7-10 days 15 - 17 oC
more then 10 days 14 - 15 oC
It is not recommended to set eggs immediately, as this reduces hatchability. Storage should be at least 1 day, preferably 2 days.
When eggs are stored at lower temperatures, condensation must be prevented, as this will increase the number of exploders and has a very negative effect on chick quality
Relative humidity
Relative humidity controls the moisture loss. In principle, we want to reduce the moisture loss during storage by increasing the relative humidity. However, relative humidity is not as important as time or temperature, as the risk of condensation or wetting the eggs by adding humidity is more important than the prevention of moisture loss itself. If it can be maintained without adding moisture, an optimum relative humidity during storage is 65-75%.
When the storage temperature is reduced, due to longer storage periods, the moisture loss of eggs will go down by itself. This is because the water vapour pressure deficit (the driving force for moisture loss between inside and outside of the egg) is reduced.
