Auditory stimulus intensity and the neonatal approach response of domestic chicks (Gallus gallus)

Three experiments were performed to investigate the neonatal approach response of domestic chicks and its behavioural accompaniments to three intermittent auditory stimulus intensities (62, 67, and/or 75 db) and a baseline condition. Chicks from a sample of the Cornell Randombred population were tested at 24, 48, 72, 96, 120, and/or 144 h of age. The results indicated that louder auditory stimulus intensities are generally approached more rapidly. Also, more snuggling and contentment peeping and less orientation away and leaving the goal area occured at higher levels of auditory stimulus intensity. Pecking scores increased with increasing age. Behaviours, other than approach speed, were typically more sensitive to changes in chick respositivity.