Pre-incubation holding of hatching eggs

The time between a hatching egg being produced and set in an incubator can be divided into a laying house period and a storage period. The period in the laying house affects hatching results by the stage of embryonic development at oviposition as well as by the subsequent environmental conditions. Advanced embryonic development at oviposition or prior to storage seems to improve hatchability, especially when storage is prolonged. Stage of embryonic development at oviposition is influenced by parental age, strain, individual bird variation and clutch length. After oviposition and before storage embryonic development can be influenced by the type of nest, egg collection pattern and temperature.During storage, hatchability is influenced by the length of the storage period, temperature, humidity, gaseous environment and the orientation of the eggs. A decrease in hatchability can be detected in eggs stored for 2–3 days or more. Storage temperature should be decreased with extended length of storage. Temporary heating before incubation and enclosing eggs in plastic bags during storage improves hatchability, especially when storage is prolonged. A high humidity during storage also improves hatchability, probably due to a reduction in water loss. The changes in albumen pH during storage are discussed in so far as they provide a possible explanation for relationships between environmental conditions during storage and hatching results.