A simple and low-cost method of "listening" to chicks may allow welfare issues to be picked up at the earliest possible opportunity, according to new research led by the University of Plymouth in the U.K.
In commercial chicken farming, thousands of newly hatched chicks are reared in batches. A team of animal welfare and behavior scientists from across the U.K. collected acoustic recordings in 12 such typical flocks of 25,000 chicks.
In nature, when uncomfortable or uncertain of their surroundings, chicks would attract the hen with a loud and distinctive distress call. In this study, the researchers demonstrated that these calls could be clearly picked up above other noises such as regular calling and farm machinery, an announcement from the University of Plymouth said.
However, where previous research has linked distress calling to stress and anxiety-like states in chicks, this study also shows that it could predict flock-level behavior, future growth and the mortality rate.
The results suggest that distress calling may be an "iceberg indicator" — a single measure that captures a range of welfare information at once, the researchers said.
The study, published in the Journal of the Royal Society Interface, involved researchers from the University of Plymouth, University of Roehampton, Scotland's Rural College and Newcastle University. It was funded by the Biotechnology & Biological Sciences Research Council (BBSRC) in an Innovate UK partnership with Greengage Lighting Ltd.
"On their first day in a barn, all chicks are going to call, because they are in strange surroundings, 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," lead author Dr. Katherine Herborn, lecturer in physiology and behavior at the University of Plymouth, said. "With more than 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."
Lucy Asher, Newcastle University professor in animal behavior informatics and principal investigator on the BBSRC project, added: "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. 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," Asher said.
The method used in the research involved measuring the "spectral entropy" of the soundscape — a value that describes how sound can vary from a clear, tonal note to white noise, the announcement explained.
As increasing numbers of chicks call in unison, the usual background noise of the farm becomes overall more tonal. This computationally simple way of counting distress calls could act as an early warning signal to farm staff that chicks require attention and, ultimately, improve chick welfare across their lifetimes, the researchers said.
The findings support previous studies on the benefits of automated monitoring of livestock for real-time warnings of emerging welfare concerns, the university noted. The findings also emphasize the importance of using animal-centered behavioral and emotional welfare indicators alongside traditional environment and productivity monitoring on poultry farms to improve conditions from the birds' own perspective.
Dr. Alan McElligott, reader in animal behavior at the University of Roehampton, added, "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."