Scientists have created a system of automatic recognition of alarm signals of chickens, which will help to warn farmers that newborn Chicks feel uncomfortable. The computer program measures the spectral entropy of the sound environment, which correlates with the weight and mortality of Chicks. Article published in the Journal of the Royal Society Interface.
In response to stress chickens make frequent repetitive high-pitched sounds that indicate their negative emotional state. When Chicks just hatched, they use squeak to attract the attention of chicken, but once the animals get used to the environment and find sources of food and water, the number of alarms is considerably reduced. If this behavior continues, it is usually associated with discomfort such as strong heat or cold, potential threat, lack of access to the necessary resources or social isolation.
Katherine Herborn (Katherine A. Herborn) from Plymouth University, together with colleagues decided to test whether a connected peep of chickens living on the farm, with their comfort, weight, and mortality. To do this, the researchers recorded the sounds of the 12 groups of Chicks, numbering not less than 25 thousand individuals. Using an algorithm, which measured the spectral entropy audio, zoologists have separated high babies from background noise. Spectral entropy describes the complexity of the system: for example, it will have a low value, and the white noise was very high. Compared to the rest of the sounds alarms chickens quite loud, and they are characterized by frequent repetition, so they cause a noticeable change in the overall acoustic environment.
Spectral entropy were correlated with manual counting of disturbing squeaks of the chickens (Spearman correlation coefficient -0.88), indicating that the correctness of computer programs. As expected, the number of stress-related sounds decreased with age of nestlings, which was reflected in the increase of spectral entropy. Zoologists also found that in groups where recurring alarms were particularly numerous and did not cease with the passage of time, the chickens gained less weight not only on the next day, but a month later, and in these groups had a greater number of premature deaths. In addition, the spectral entropy was higher when the Chicks were off in the big and close pile is consistent with the results of the experiment found a correlation between this behavior and the stress caused by cold.