Producers may soon be able to monitor for stress in laying flocks by simply listening for any changes in the sound they produce.

Alleviating stress in commercial flocks of laying hens and broilers is important not only because it improves the overall welfare of the birds, but also because stress is a known enemy of production efficiencies,” said Michael Darre, a professor at the Department of Animal Science, University of Connecticut.

“Chronic stress has been shown to reduce egg production, reduce growth and meat yields, and lower immune system function. And yet finding a practical, non-invasive way to assess stress in chickens has proven to be a difficult challenge.”

Currently, the only clinical tool for directly measuring stress levels is taking a blood sample and analysing levels of traditional stress indicators such as cortisol and adrenaline. And this itself is likely to induce further stress to the bird.

Furthermore, there is the long time it takes to analyse the blood.

He believes the analysis of noises made by birds may provide the answer, because it is non-invasive and provides immediate and accurate feedback on levels and types of bird stress.

Dr Darre’s first task was to determine if vocalisation patterns were the same for all types of stress and he discovered that they were not. “For example, vocalisation patterns have been found to be different for stress due to handling and stress due to overcrowding.”

The analysis was carried out by digitally recording layers under different types of stressful conditions, and then, after removing background noise, analysing the recordings. Now they are learning how to interpret what birds are “saying”.

Ultimately, the goal is to develop a “black box” that can be placed in poultry houses that allows producers to remotely monitor their birds, notifies producers when it detects stress vocalisations. And it will also identify the type of stress, so that action can be taken immediately to address the problem.

“This kind of monitoring would help reduce overall stress in flocks and be a great step forward in improving the welfare of commercial bird flocks. This in turn would benefit producers, and ultimately the consumer through improved egg-laying and meat output due to the known benefits of keeping birds in a lower-stress environment,” said Dr Darre.