Effects of hatching system on broiler activity measured individually by an ultra-wideband tracking system

Broilers usually hatch in hatcheries without access to feed and water until placement at the farm, which can affect their health, resilience and welfare. Therefore, alternative concepts have been developed, such as providing chickens with early nutrition in the hatchery or hatching eggs on-farm. However, information on the resilience and welfare of chickens hatched in these systems is limited. Changes in broiler activity are a promising indicator for various resilience and welfare threats. Sickness and lameness for instance have been associated with lower activity levels in broilers. With modern sensor technology, it is possible to automatically record group- but also individual activity patterns. The aim of this study was to assess the effects of hatching system on broiler activity in general and after the challenging situation of vaccination. Therefore, a proof-of-principle-experiment was performed with chickens that hatched either conventionally in the hatchery (HH), in a system which provided feed and water in the hatcher (HF, hatchery-fed) or on-farm (OH). The animals were reared in 3 floor pens (one pen/hatching system, 30 animals/pen) in a room, in which an ultra-wideband (UWB) tracking system was installed. At d14, active tags of the UWB system were attached to 5 chickens/pen. The distances moved (DM) by the birds were tracked for 4h/d until d34. At d28, all chickens were vaccinated individually with a live vaccine against Infectious Bronchitis. There was a significant age x hatching system interaction for the DM by the chickens (F2,306 = 5.57, P<0.001). During the 3rd week of life, HH chickens moved less than HF and OH chickens, whereas there was no difference between HF and OH chickens in week 3, and between all three groups in week 4 and 5. Within all groups, DM differed between individual chickens (HH: F4,90 = 46.42, P<0.001; HF: F4,90 = 48.50, P<0.001; OH: F4,90 = 80.46, P<0.001). To analyse the effects of the vaccination challenge, DM were tested for within-subject factors (DM on 3 days before and after the challenge, respectively) and between-subject factors (hatching system). DM did not differ within subjects. However, there was an effect of between-subject factors for the three days following the challenge, with HH chickens moving longer distances than HF and OH chickens (P<0.001). The results indicate that hatching system affected broiler activity at specific ages and days after a vaccination challenge, with chickens from two alternative systems showing similar activity patterns. Within all 3 hatching systems, activity also differed among individual birds.