Automatic Identification of Activity and Spatial Use of Broiler Chickens with Different Gait Scores

Abstract

<abstract><title><italic>Abstract. </italic></title> This article extends existing research on the activity of broiler chickens and describes a novel system to automatically assess the spatial use of chickens with different gait scores using imaging technology. For this study, 30 broiler chickens (Ross 308) at the age of 26 days were visually scored by experts for their degree of lameness, and five birds per gait score group (GS0 to GS5) were used in the experiments. The experimental period of 12 days was subdivided into two periods of six days. The first experiment (days 1 to 6) was conducted in a laboratory test installation consisting of a stainless steel compartment with six integrated pens. Five birds with the same gait score were housed in each pen, resulting in a stocking density of five birds m^-2. The chickens’ activity was automatically recorded for 6 h each day (days 1 to 6), resulting in 432 data sets per gait score group. In the second experiment (days 7 to 12), the separation fences between the pens were removed. Thus, the different chicken groups were merged into one group and were kept together within the stainless steel compartment. A novel monitoring system with color tracking features was developed to calculate the activity of the merged chickens. Using this system, the chickens’ activity was automatically monitored for 6 h each day, resulting in another 432 data sets. Additionally, the spatial use of broiler chickens in relation to different lameness degrees was investigated with this fully automated monitoring system during the second experiment. A significant relationship between the gait score given by an expert and the activity monitored by the image analysis system was observed for both experiments. The broilers with gait score 3 (GS3) showed significantly higher activity than other gait scores in both experiments (p < 0.05). GS4 and GS5 showed significantly lower activity (p < 0.05). During the second experiment, the spatial use of mixed chickens was investigated, revealing that GS0 and GS3 chickens explored the compartment area more than chickens with higher gait scores.