This paper extends existing research on activity of broiler chickens and describes a novel system to automatically assess the spatial use of chickens with different gait scores by image technology.
For this study, 30 broiler chickens (Ross-308) at the age of 26 days were visually scored by the experts for their degree of lameness according to the method of Kestin et al. (1992) and five birds per gait score group (GS0 to GS5) were used in the experiments.
The experimental period of in total 12 days was subdivided into two times six days. The first experimental period (day 1 - 6) was conducted in a laboratory test installation consisting of a stainless steel compartment with six integrated pens. Five birds (each having the same gait score) were housed in each pen resulting in a stocking density of five birds /m2. The chicken’s activity was automatically recorded on each day of the first experimental period (day 1-6) for six hours resulting in 432 data sets per gait score group. In the second experimental period (day 7–12), the separation fences between all pens were removed. Thus, the different chicken groups were merged to 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. The activity was automatically monitored by this system for six hours each day resulting in another 432 data sets. Additionally, the spatial use of broiler chickens in relation to different lameness degrees was investigated by this fully-automated monitoring system during the second experimental period.
A significant relation between the gait score given by an expert and activity automatically monitored by image analysis system was observed for both experimental periods. The broilers with gait score 3 (GS3) showed a significantly higher activity than other gait scores in both experimental periods (P<0.05). GS4 and GS5 showed a significantly lower activity (P<0.05). During the second experimental period the spatial use of mixed chickens was investigated revealing that GS0 and GS3 chickens explored the compartment area more than chickens with a higher gait score.