BACK TO QUEBEC CITY 2002 TITLES
The effects of maternal
sounds on chicks
M.B. Woodcock, M.A. Latour
and E.A. Pajor
Purdue University, West
Lafayette, USA
A serious poultry welfare and production issue is ensuring that young chicks locate food and water quickly after hatch. Hens use vocalizations and visual cues to aid chicks in finding food. Although vocal communication between the hen and chick occurs before chicks hatch, the influence of these vocalizations on chick behavior after hatch is unknown. We carried out a series of 4 experiments that investigated if maternal vocalizations and other sounds played to chicks before they hatch influenced hatch synchrony or chick’s behaviour in a series of choice tests. In the first experiment, 184 eggs were divided among eight incubators, 23 eggs per incubator; four incubators were played the recorded vocalizations of an unrelated broody hen. The other four incubators received no sound as a control. The experiment was replicated three times. Playing sound had no significant effect on hatch synchrony (Hatch window, sound 21.67 ± 1.92; no sound 21.5 ± 1.92; Mann-Whitney, P <0.886). We then tested 144 chicks (72 controls and 72 chicks that had been played vocalizations before hatch) in a Y-shaped maze with two speakers at either arm. Chicks were given a choice between no sound or maternal vocalizations. Significantly more sound treated chicks chose maternal vocalizations than the control chicks (61/72 vs 40/72, binomial test P < 0.001). In the next 3 experiments eggs were played maternal vocalizations or various tones (Experiment 2, 700 Hz; Experiment 3, 1700 Hz; Experiment 4, 700 Hz with increasing rate). In each experiment, 69 eggs were randomly assigned to three treatments: control (C), tone (T) or maternal vocalization (MV) (23 eggs per treatment). Sounds were played to the eggs 3 days prior to hatch. Once hatched, the chicks were then placed into a choice discrimination test apparatus and observed. In all 3 experiments, chicks showed preference for maternal vocalizations (145/180 chicks). However, those chicks hearing maternal vocalizations during incubation selected maternal vocalizations slightly more frequently in the choice discrimination test than other sound treatments, (exp 2, MV 15/16, T & C 10/16; exp 4, MV 15/15, T 13/15, C 11/15). The effects of sounds in the incubator require additional research. It is possible that playback of maternal vocalizations at feeders could reduce time taken for chicks to find food, increase feed consumption and improve chick welfare.