Enhancing Range Use in Free-Range Laying Hen Systems: The Impact of Vegetation Cover over Time.

Outdoor ranges in free-range laying hen systems are often underutilised, likely due to their open, uncovered nature. Given that the domestic chicken's ancestor inhabits forests with high canopy cover, similar habitat preferences can be expected. To assess the impact of vegetation cover, range use was recorded on two outdoor ranges before and one and two years after planting bushes. A barrier tape grid was placed on each outdoor range, images were taken every 10 min over three days and hens per quadrant were counted. Data were analysed using general additive models. On both outdoor ranges, the number of hens increased in quadrants with newly planted bushes. While hen numbers declined with increasing distance from the shed in all three years, this effect diminished in the two years after planting. Furthermore, hens on both outdoor ranges in all three years showed diurnal patterns in range use, resembling the natural behaviour of their ancestor. The findings support the hypothesis that vegetation cover plays a crucial role in promoting more even range use, including in parts further away from the shed. To encourage natural behaviour and mitigate the negative effects of poor range utilisation, outdoor ranges should incorporate evenly distributed vegetation cover.