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Open AccessArticle

Assessment of Laying Hens’ Thermal Comfort Using Sound Technology

College of Water Resources & Civil Engineering, China Agricultural University, Beijing 100083, China
Division Measure, Model & Mange Bioresponses, Department of Biosystems, KU Leuven, Kasteelpark Arenberg 30, 3001 Heverlee, Belgium
Authors to whom correspondence should be addressed.
Sensors 2020, 20(2), 473;
Received: 14 December 2019 / Revised: 5 January 2020 / Accepted: 11 January 2020 / Published: 14 January 2020
(This article belongs to the Special Issue Sensors in Agriculture 2019)
Heat stress is one of the most important environmental stressors facing poultry production and welfare worldwide. The detrimental effects of heat stress on poultry range from reduced growth and egg production to impaired health. Animal vocalisations are associated with different animal responses and can be used as useful indicators of the state of animal welfare. It is already known that specific chicken vocalisations such as alarm, squawk, and gakel calls are correlated with stressful events, and therefore, could be used as stress indicators in poultry monitoring systems. In this study, we focused on developing a hen vocalisation detection method based on machine learning to assess their thermal comfort condition. For extraction of the vocalisations, nine source-filter theory related temporal and spectral features were chosen, and a support vector machine (SVM) based classifier was developed. As a result, the classification performance of the optimal SVM model was 95.1 ± 4.3% (the sensitivity parameter) and 97.6 ± 1.9% (the precision parameter). Based on the developed algorithm, the study illustrated that a significant correlation existed between specific vocalisations (alarm and squawk call) and thermal comfort indices (temperature-humidity index, THI) (alarm-THI, R = −0.414, P = 0.01; squawk-THI, R = 0.594, P = 0.01). This work represents the first step towards the further development of technology to monitor flock vocalisations with the intent of providing producers an additional tool to help them actively manage the welfare of their flock. View Full-Text
Keywords: animal vocalisation; THI; SVM; laying hens; animal welfare animal vocalisation; THI; SVM; laying hens; animal welfare
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Du, X.; Carpentier, L.; Teng, G.; Liu, M.; Wang, C.; Norton, T. Assessment of Laying Hens’ Thermal Comfort Using Sound Technology. Sensors 2020, 20, 473.

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