Distress calls from baby chicks predict the health of the whole flock
Scientists at the University of Plymouth have found that distress calls from newly-hatched chicks contain a wealth of important information. The experts discovered that these calls can be used to predict the behavior, growth, and mortality of entire flocks that contain thousands of chicks.
“By analyzing the calls chicks make in their first few days of life, it seems we are able to predict weight gained and the number of deaths in the whole flock for the whole life,” said study co-author Professor Lucy Asher.
“This means we could have a very powerful tool to help chicken welfare. What is particularly useful is that this welfare indicator can be used early on in life, whereas most chicken welfare indicators are taken later in their life when it is too late to make major improvements.”
“As an added benefit this study shows how we can measure chick calls automatically, meaning no extra work for farmers, but more information to help them improve chicken welfare.”
Commercial chicken farms rear young chicks in large groups of hundreds to thousands. For the current investigation, a team of animal welfare and behavior scientists captured acoustic recordings of 12 flocks of 25,000 chicks.
In a natural environment, chicks use loud and distinctive distress calls to demand attention from the mother hen when they feel uncertain or unsafe. The researchers found that these calls can be clearly heard above all other noises, including regular chick calls or farm equipment.
Previous studies linked distress calling to anxiety in baby chicks. But the new research suggests that the distinctive calls are much more significant, serving as an “iceberg indicator” – a single source of a range of welfare information.
“On their first day in a barn, all chicks are going to call because they are in strange surroundings,” explained study lead author Dr. Katherine Herborn.
“But after that they learn where to find food and water and settle into that new world, so if you are still hearing a lot of distress calling after a few days it could be a sign there is something wrong.”
“With over 50 billion birds being produced each year, tools to support simple interventions at the right time could potentially have big impacts on welfare and quality of life for these birds.”
The technique used for the analysis measured the “spectral entropy” of the soundscape. The spectral entropy is the value that describes the complexity of a sound, which can vary from a clear, tonal note all the way to white noise.
When multiple chicks are calling out at the same time, the background noise across the farm becomes more tonal. This provides a computationally simple system for counting distress calls, which could ultimately highlight early warning signals and improve the health of chicks over their lifetime.
“The results of this research show how useful vocalizations can be for monitoring welfare, and especially in an age when animal welfare needs should be central to progress in precision livestock farming,” said Dr. Alan McElligott.
The study is published in the Journal of the Royal Society Interface.