3 Drawbacks of long egg storage
It is well known that storing eggs longer than seven days decreases the hatchability. In fact, the longer eggs are stored, the higher the losses in hatchability. Stored eggs have a higher rate of embryonic mortality between days two and three of incubation, and need more time to complete incubation. This causes some live chicks to be rejected at take-off because they hatch too late. The causes of this hatchability loss are deterioration of the albumen, and necrotic cell death. The developmental stage of the embryo, the number of viable cells and the pH of its micro environment probably affect embryo viability most during storage and early incubation, and are hence important for the ultimate hatchability.
With increased storage periods, there is a rise in the number of mitotic (blocked in metaphase and dying during storage) and necrotic indexes. As initiation of mitosis can probably occur in eggs stored at or below 20°C, eggs stored for a long period should be stored at a temperature below 20°C (between 10- 15°C) in order to reduce this cellular activity. Moreover, changes in albumen pH and albumen viscosity may be important factors in embryo viability. The embryo is in direct contact with the yolk on one side (yolk pH being 6) and close to the thick layer of albumen on the other side (pH being close to 9 after four days of storage). This difference in pH between albumen and yolk is necessary for particular transport functions through the vitelline membrane, but prolonged exposure to high albumen pH levels, due to prolonged storage, can become detrimental to the embryo, since optimum pH for embryonic development during the first few days of incubation is between 7.9 and 8.4.