Higher fear of predators does not decrease outdoor range use in free-range Rowan Ranger broiler chickens

Organic chicken production is currently experiencing a boom in Sweden, but has only recently gained access to a commercial slow-growing broiler strain, the Rowan Ranger. While these chickens are reported to grow at rates better suited to organic production than previously available strains, anecdotal evidence suggested increased fearfulness in this strain and concerns were raised that this may deter the birds from accessing the range. We subjected Rowan Rangers and fast-growing Ross 308 raised on the same organic farm to a set of behavioural tests while also tracking activity and outdoor use. The results suggest that although Rowan Rangers indeed show longer durations of tonic immobility, an index of predator-related fear, both strains made an outdoor visit on average once every 1.5 h and typically spent around 5% of their days in the range. Overall however, our results support the transition to Rowan Rangers in organic chicken production in Sweden.Funding Agencies|Swedish research council Formas [2013-293]; Linkopings Universitet; Formas