Influence of pre-incubation treatment on hatching results of broiler breeder eggs produced at 37 and 59 weeks of age.

1. The influence of temperature in the nest box, temperature during storage, storage time and pre-setting temperature on the hatchability of broiler breeder eggs produced by birds of 37 and 59 weeks of age was examined. 2. All treatments that can be characterised as being less optimal for embryo survival than the control treatment affected the hatchability of fertile eggs more in the case of eggs produced by older birds. 3. A higher temperature in the nest box, longer storage periods, higher storage temperature, especially at longer storage periods, and higher pre-setting temperature significantly reduced the hatchability of fertile eggs from the older birds. 4. For the younger birds, a significant reduction of hatchability was found only for the longest storage period.