EFFECTS OF VISUAL-STIMULI AND NOISE ON FEAR LEVELS IN LAYING HENS

Conveyors have been proposed to improve bird welfare during handling p rocedures. Speeds of conveyors have been recommended, though the effec ts on bird welfare have not been addressed. During travel no horizonta l forces are applied. Therefore visual perception of speed may play an important role if birds find movement frightening. Stationary birds w ere subjected to moving stimuli of 0.33, 0.67 and 1.00 m s-1 by being placed between side-wall conveyor belts to present a moving background . Fear levels were measured using tonic immobility and were compared w ith the fear levels of birds receiving no moving stimulus. The effect of the noise of the conveyors was also investigated. No significant di fference was found between birds exposed to the noise of the conveyors compared with those receiving no noise. Similarly no significant diff erences were found in fear levels for groups exposed to the different visual stimuli, suggesting that fear does not increase with increased perceived speed. In fact trends in the data indicate that fear levels might decrease with the increased perceived speed. Further investigati ons could determine whether there is any real effect of perceived moti on on induced fear levels and whether there is a maximum speed beyond which birds may become frightened.