Spectral entropy of early-life distress calls as an iceberg indicator of chicken welfare

Katherine Herborn*, Alan McElligott, MA Mitchell, V Sandilands, Brett Bradshaw, Lucy Asher

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)
61 Downloads (Pure)


Chicks (Gallus gallus domesticus) make a repetitive, high energy 'distress' call when stressed. Distress calls are a catch-all response to a range of environmental stressors, and elicit food calling and brooding from hens. Pharmacological and behavioural laboratory studies link expression of this call with negative affective state. As such, there is an a priori expectation that distress calls on farms indicate not only physical, but emotional welfare. Using whole-house recordings on 12 commercial broiler flocks (n = 25 090-26 510/flock), we show that early life (day 1-4 of placement) distress call rate can be simply and linearly estimated using a single acoustic parameter: spectral entropy. After filtering to remove low-frequency machinery noise, spectral entropy per minute of recording had a correlation of -0.88 with a manual distress call count. In videos collected on days 1-3, age-specific behavioural correlates of distress calling were identified: calling was prevalent (spectral entropy low) when foraging/drinking were high on day 1, but when chicks exhibited thermoregulatory behaviours or were behaviourally asynchronous thereafter. Crucially, spectral entropy was predictive of important commercial and welfare-relevant measures: low median daily spectral entropy predicted low weight gain and high mortality, not only into the next day, but towards the end of production. Further research is required to identify what triggers, and thus could alleviate, distress calling in broiler chicks. However, within the field of precision livestock farming, this work shows the potential for simple descriptors of the overall acoustic environment to be a novel, tractable and real-time 'iceberg indicator' of current and future welfare.

Original languageEnglish
Article number20200086
JournalJournal of the Royal Society Interface
Issue number167
Early online date10 Jun 2020
Publication statusPrint publication - 24 Jun 2020


  • Gallus gallus domesticus
  • animal welfare
  • bioacoustics
  • iceberg indicator
  • precision livestock farming


Dive into the research topics of 'Spectral entropy of early-life distress calls as an iceberg indicator of chicken welfare'. Together they form a unique fingerprint.

Cite this