For shipment of eggs over long distances, often carton boxes are used. The eggs are then stored on paper trays and packed in the boxes either at the farm or at a packing station or hatchery. In these boxes, eggs are protected against shocks and rough handling, and their temperature will not change very rapidly when outside temperature changes.
Although shipping eggs in carton boxes is a very good method, a couple of things have to be taken into consideration.
- Eggs in carton boxes do not change rapidly in temperature. Their half-time (the time needed to go through half of the temperature difference) is often more than 24 hours, and when packed in stacks the half time can increase to 48 hours or more. If eggs are packed when still (too) warm, it also means that they will hardly cool down inside the boxes, and their temperature will stay warm for a very long time, with sometimes detrimental effects on hatchability.
- When eggs are fumigated, for instance with formaldehyde, and then immediately packed in boxes, the fumigation gases can stay for a very long time in the boxes. Especially when carton trays are used, a lot of formaldehyde will be taken up during fumigation by the trays and eggs, and released in the boxes. This can have detrimental effects on the embryos.
- Although carton boxes are very rigid, they are very sensitive for moisture and then lose rapidly their strength. When eggs are packed in a dry environment, transported to a hatchery and then stored in a cold environment with a high relative humidity, the stacks can collapse after a couple of days with high number of cracks and breakages.