by Marleen Boerjan, Director of R&D, Pas Reform Academy
The care of hatching eggs during storage – at the farm, in transit or at the hatchery – is an important aspect of hatchery management that aims to preserve the vitally of the embryo.
With optimum temperature and relative humidity, hatching eggs can generally be stored for one week without significantly reducing hatchability or chick quality. Eggs stored for longer that this are known to benefit from lower temperatures (12-14ºC) (Fasenko, 2007; personal experience).
Pre-storage incubation, i.e. incubating eggs before they are placed in the storage room, is a new approach to storage management that aims to develop the embryo to the so-called hypoblast stage: a stage of embryonic development that is better able to survive storage.
According to Fasenko (2007), broiler hatching eggs reach the hypoblast stage after six hours of pre-storage incubation, turkey embryos after 12 hours.
Layer hen hatcheries have reported 3-7%more females after pre-storage incubation for 3-6 hours, when eggs are stored for more than 11 days (Lohmann Tierzucht, Management Guide).
In the broiler industry, positive pre-storage incubation results show at least a 1% increase on expected hatchability, when the eggs undergo pre-storage incubation of 3-6 hours on arrival at the hatchery (Fasenco et al., 2001; Fasenco, 2007). Eggs scheduled for storage for more than seven days after production benefit most from pre-storage incubation.
However, many questions, mainly concerning timing and duration, continue to surround the adoption of pre-storage incubation in routine management practice.
Considerations for the practice of pre-storage incubation
Pre-storage incubation is only beneficial if the embryos in the eggs are in a very early stage of development. For example: if nest temperatures are high and the eggs stay in the nest too long, the embryos may develop beyond the storage resistant stage, when pre-storage incubation will increase early embryonic mortality.
Small-scale experiments will help identify the best timing and length of pre-storage incubation for your own hatchery and eggs types (see below).
To assess results in your own hatchery:
• Place eggs for pre-storage incubation on setter trays in setter trolleys, to ensure uniform egg temperature during incubation.
• Do not incubate eggs on paper trays or in boxes. This guarantees heterogeneous egg/embryo temperatures, resulting in high levels of early mortality.
• Disinfect eggs as long as pre-storage incubation is preformed in a setter located in the setter room (“clean area”). Ideally use to the egg storage room.
• Pre-storage incubation can be applied when eggs arrive at the hatchery 3-4 days after production and are scheduled for more than four days extra storage at the hatchery.
To assess performance benefits and establish pre-storage incubation protocols in hatchery:
• Egg selection: per egg type, there trolleys for pre-storage incubation with one trolley (same batch) for control.
• Disinfect: if the eggs are incubated in a normal routine setter.
• Pre-storage incubation: place trolley(s) with (disinfected) eggs in a running setter at incubation temperature. Incubate the eggs for 3, 6 and 9 hours. Control eggs stay at storage temperature.
• Return pre-storage incubated eggs to the storage room (with control eggs) for at least seven days before starting the normal incubation cycle.
• Run normal incubation with both the pre-storage incubated eggs and the control eggs.
• Evaluate: compare hatchability – pre-storage incubated eggs vs. control eggs.
• Repeat this experiment with eggs from at least three different flocks.
• Evaluate all results. If positive, adopt pre-storage incubation routine as indicated by results.