The Healthy Livestock approach: welfare and behaviour of broiler chickens hatching in different systems.

The peri-hatching environment can affect health, resilience and welfare of broiler chickens in later life. Optimal early and later life conditions will likely contribute to a reduction in the use of antimicrobials in broiler production. The aim of this study was to investigate effects of recently developed hatching systems on the well-being of broiler chickens in early and later life. Therefore, a grow-out experiment was performed with chickens that hatched either conventionally (HH, hatchery hatched, no light, feed or water in the hatcher), in a system which provided feed and water in the hatcher (HF, hatchery fed) or on-farm (OH, on-farm hatched, where feed and water were available after hatch and, in addition, transport of day-old chickens from hatchery to farm was not necessary). The animals were reared in three batches, in 12 floor pens/batch (1,150 animals/pen) with a total of 12 replicates of each treatment. Several animal-based indicators were assessed following standard protocols: plumage cleanliness, footpad dermatitis (FPD), hock burn, skin lesion (at d21 and 35 of age), and gait score (d35). Furthermore, a set of behavioural tests was carried out: novel environment (d1 and 21), tonic immobility, novel object, and avoidance distance test (d4 and 35). Plumage cleanliness, hock burn and skin lesion were affected by age but not by hatching system, with older broilers scoring worse than younger ones (P<0.05). An effect of hatching system was only found for FPD, with HH chickens having more frequently and more severe lesions compared to HF and OH chickens (P<0.05). All responses measured in the behavioural tests were again affected by age but not by hatching system. In later life, chickens acted significantly less fearful than during the first days of life. The results indicate that conventionally hatched chickens scored significantly worse for the key indicator FPD, whereas, in general, hatching system seemed to have minor effects on welfare and behaviour of broilers.