Domestic chickens display signs of empathy, the ability to "feel another's pain" that is at the heart of compassion, a study has found.
The University of Bristol discovery has important implications for the welfare of farm and laboratory animals, say researchers.
Empathy, long thought to be a defining human trait, causes one individual to be affected by the emotions of another. The research demonstrated that hens were able to empathise with their chicks.
When scientists ruffled the feathers of chicks with an air puff, they showed signs of distress that were mirrored by their mothers, including an increase in heart rate and lower eye temperature.