Large variation in the movement of individual broiler chickens tracked in a commercial house using ultra-wideband backpacks.

Our understanding of the movement patterns of individual broiler chickens in large flocks is extremely limited. Here we report the use of a Real Time Locating System to track individual broilers in a house of 28 000 birds. Broilers were fitted with backpacks containing ultra-wideband tags on day 21 (N = 8 broilers) or day 24 (N = 9 broilers), with tags recording positioning and distance data until Day 38. Tagged birds were penned overnight on Day 31 to avoid 'thinning'. We found no clear evidence of broilers consistently creating similar sized "home ranges". Some broilers spent most time < 10 m from where they were originally found while others visited at least 90% of the house in the period before thinning. While some broilers rapidly returned to the area they were collected from at thinning, the majority did not. Movement data suggested that broilers that restricted themselves to smaller areas of the house were not necessarily less active. Although there was an average reduction in movement with age, this was not linear and there was individual variation. There was also no clear association between movement patterns and broiler weight or gait score, suggesting a more complicated relationship between activity, ranging and some welfare measures.