Domestic chicks' runway responses to video images of conspecifics

Because chickens are highly social animals, live conspecifics are often use d to provide an incentive or goal in studies of gait, sociality or fear tha t require the bird to traverse a runway. However, the variable behaviour of the stimulus birds can influence the approach/avoidance responses of the t est birds and thereby confound the results. Because chickens modify their b ehaviour readily and appropriately to a variety of video images, including social stimuli, we asked if video playback might represent easily controlla ble and standardized alternatives to live birds. Female ISA Brown chicks we re housed in groups of eight and then exposed to a blank illuminated televi sion for 10 min per day from 2 to 7 days of age. At 8 or 9 days of age they were placed individually in the start box of a 1.6 m long runway and we re corded their responses to a monitor displaying selected video images that w as situated in the goal box at the opposite end of the runway. In Experimen t 1 chicks approached a monitor playing the video image and soundtrack of f eeding chicks significantly sooner than one of a goal box with the food dis h and background noise. In Experiment 2, chicks were exposed to the same vi deo of feeding conspecifics with or without the associated sounds or to a v ideo of the goal box with or without the chick soundtrack. Both the videos of other chicks elicited faster approach than did those of the goal box and the sound and silent versions were equally attractive. Adding the soundtra ck of feeding chicks to the goal-box video failed to increase its attractiv eness. The present results suggest that chicks are attracted towards televi sed images of other chicks. They also indicate that the visual and auditory components of the video stimuli did not exert additive effects and that ap proach reflected attraction to the visual image. Collectively, our findings suggest that video playback of selected social stimuli, such as feeding co nspecifics, could be a valuable tool in tests requiring voluntary locomotio n along a predetermined path. (C) 2001 Elsevier Science B.V. All rights res erved.