An epidemiological study of the hatchability in broiler breeder flocks

The aim of the present retrospective longitudinal study was to identify factors that significantly influenced the hatchability observed during the period from 1996 to 1998. Data from 112 Ross 208 breeder flocks in 39 breeding farms were included in a repeated-measures analysis with the flock-level "interval-specific" hatchability of the eggs as outcome variable. The overall mean of interval-specific hatchability in the study was 75.9% (95% confidence interal: 75.3 to 76.6%). The hatchability was influenced by the storage time from lay until incubation and whether the farmers delivered floor eggs for hatching. The method used for disinfecting the hatching eggs and the flock average slaughter weight were significantly associated with the hatchability. A significant effect of time (production year) and flock size were also found on the hatching results. The results showed that several factors may influence the hatchability, the most detrimental being long egg storage time. With an optimization of the capacity and administration of the hatcheries, it would be possible to improve the hatching results.