In the commercial poultry industry, hatching noise (roughly ≤ 3 kHz) may negatively influence chick communication. Chicks in a noisy incubator may modify their vocal signals to minimize masking by environmental noise, which makes vocalization a potential indicator of welfare status of chicks. The aim of this research was to identify effects of hatching noise on chick vocalisation variation.A total of 500 laying hen eggs were hatched in two identical climate respiration chambers, used as incubators, with different noise levels from day 17 until 21. The high noise chamber (90-100 dB) consisted of the continuous playback of noise from a commercial hatcher; while the noise level of the low noise chamber was kept at 60-70 dB. From day 19 until 21 of incubation, the chick vocalisations (number, frequency of the highest amplitude (FHA)) were recorded by 20 wireless microphones in each chamber and further analysed by Avisoft®. Two types of vocalisations were classified according to the structures. Sound parameters were analysed with general linear models by using an unbalanced ANOVA design to identify effects of noise on the number of vocalisations and FHA.Significantly fewer vocal signals were recorded in the high noise chamber compared with the low noise chamber (6.43±0.60 vs. 18.34±0.39 calls per 10s; p<0.001). Significant differences were detected in FHA between the two types of calls in the low noise hatching treatment (p<0.001). The FHA of low frequency calls increased significantly in the high noise environment (4.04±0.076 vs. 3.67±0.026 kHz; p<0.001), while the FHA of high frequency calls only showed a trend to increase (4.14±.027 vs. 4.08±0.016 kHz; p<0.1). In conclusion, chicks changed their vocal strategy in a noisy hatching environment while the use of vocalisation for poultry welfare assessment should be further studied.
|Title of host publication||Proceedings of the Benelux ISAE Conference 2016, October 13th 2016, Berlicum, The Netherlands|
|Publication status||Published - 2016|