Assessment of a global positioning system to evaluate activities of organic chickens at pasture

The aims of the present study were to assess the use of a global positioning system (GPS) monitoring device to evaluate the activities of organic chickens at pasture. Two hundred male birds from 2 strains (100 slow-growing and 100 fast-growing birds) were reared separately in 4 indoor pens (0.10 m(2)/bird), each with access to a grass paddock (10 m(2)/bird; 2 replications/genotype). During the last week of age (from 73 to 80 d of age), the kinetic activity of chickens was monitored by behavioral observations (n = 20; focal bird sampling method) and a GPS (n = 10; Super Trackstick, Atex International, Route d'Esch, Luxembourg) equipped with a universal serial bus port for quick viewing on Google Earth's 3-D model, giving information concerning the date, hour, environmental conditions, and coordinates of monitored birds. Based on the focal bird sampling method, fast-growing birds tended to stay indoors rather than forage in the pasture, whereas slow-growing birds spent more time outdoors (P < 0.05). Moreover, visual observations confirmed GPS records, whereas slow-growing birds were observed to perform more active behaviors, stand less, and spend more time outdoors than indoors. Based on GPS tracks, slow-growing chickens covered an average daily distance of 1,230 m, whereas fast-growing birds covered only 125 m. In conclusion, GPS appears to be a suitable way to evaluate the kinetic activity of chickens. We also concluded that locomotor activity, which requires a high energy consumption, is low in fast-growing birds compared with slow-growing ones, allowing the fast-growing birds to reallocate energy to productive traits.