Struggling responses of broiler chickens shackled in groups on a moving line: effects of light intensity, hoods, and `curtains

The vigorous struggling and wing flapping responses often shown by shackled chickens can compromise their welfare and seriously damage product quality. Their reduction would benefit the chickens, the farmers and the consumers. We have already shown that covering broilers' heads with an opaque hood virtually eliminated struggling when they were suspended individually from stationary shackles but the practical relevance of this finding is limited largely to those occasions when the health or growth rate of representative birds from a flock are examined. The present study moved a step closer to commercial conditions and focused on the responses of 42- to 44-day-old broilers when they were shackled in groups of three on a moving line, (observations were only carried out on the central bird in each trio). Struggling was assessed as a function of ambient illumination (