What are hens looking for? Preference testing for structural elements in free-range chickens (#559)
The provision of an outdoor range in free-range egg production is intended to allow hens to perform natural behaviours as seen in their wild ancestor the Red Jungle Fowl. However, the outdoor range is often under-utilised in commercial farms. This study aimed to elucidate what elements hens are attracted to in the range.
Three principles of cover design (height, orientation and visual density) were tested for laying hen preference in the outdoor range of a commercial egg farm using a 2x3x3 factorial design. Factors included height: 0.5m or 1.5m; orientation: vertical, horizontal or horizontal cover with one vertical side; visual density: 0% (control), 50% or 90% UV blocking cloth. These combinations resulted in 18 structures positioned 4 m from the shed. After four weeks acclimatisation the number of hens under and around a 1m perimeter of each structure was counted every 15 minutes for ten days. Data were analysed with a mixed model in SAS. A significant three-way interaction between all factors was found (P<0.0001). The most preferred visual density of these structures was 90% UV block, followed by 50%. Horizontal structures with one vertical side, of either height, were also highly preferred. Short horizontal structures were preferred to tall ones, and tall vertical structures were slightly preferred over short ones.
These results highlight the complexity of designing attractive outdoor environments for commercial chickens. It is evident that hens have retained preference for areas which provide dense cover as seen by their wild ancestors. By testing the combination of elements that hens prefer we can begin to understand how to design attractive outdoor ranges in commercial farms, however it remains to be determined if these different structures influence the performance of natural behaviours.