Effects of maternal vocalisations on the domestic chick stress response
Publication Type: |
Journal Article |
Year of Publication: |
2015 |
Authors: |
Joanne Edgar, Ilana Kelland, Suzanne Held, Elizabeth Paul, Christine Nicol |
Publication/Journal: |
Applied Animal Behaviour Science |
Keywords: |
behaviour, chicken, maternal, simulation, vocalisation, welfare |
ISBN: |
0168-1591 |
Abstract:
Although natural brooding is not commercially feasible, there is great potential to simulate aspects of maternal care to improve the welfare of farmed domestic chicks. Our previous studies showed that the presence of calm broody hens can buffer mild stress responses in chicks, although the presence of more aroused broody hens has less of a social buffering effect. Maternal vocalisations are a key component of the hens’ response to chick stress; hens vocalise for around 10% of the time when their chicks are exposed to an air-puff, with some higher responding individuals calling for up to 33% of the time. We therefore sought to determine whether playback of maternal calls at 10% and 33% proportions would alleviate stress in non-brooded chicks. We also hypothesised that prior experience of the vocalisation would be necessary for this response. 72 chicks were assigned to one of two ‘Experience’ treatments, half received prior experience of maternal call playback in their home pen and half were controls. During subsequent testing, behaviour and eye temperature responses of chick pairs were monitored before and during exposure to air puffs at 30 s intervals during three time intervals (T1: 0–3 min, T2: 4–6 min, T3: 7–9 min). During testing chicks were split into 3 groups: Group 1 received no vocalisation playback (Control), Group 2 received playback of vocalisations for 10% of the time and Group 3 received playback of vocalisations for 33% of the time (n = 12 pairs for each group). In response to the air-puff, chicks reduced sitting, pecking the environment and increased freezing. They also showed a reduction in eye temperature. All three chick groups spent the vast majority of their time freezing and there was no difference between the three groups in this behaviour. Group 2 chicks showed a lower eye temperature response during T2 and T3 compared to Groups 1 and 2, suggestive of a stress-alleviating effect. There was no effect of prior experience on the eye temperature response. The fact that vocalisation playback did not reduce freezing indicates that additional features of a broody hen are likely to be required to change the chicks’ behavioural repertoire.