A study has gained new insight
into the minds of domestic hens, discovering, for the first time, that
domestic hens show a clear physiological and behavioural response when their
chicks are mildly distressed.
The research by academics at the University of Bristol's Animal Welfare
and Behaviour research group, and funded by the BBSRC Animal Welfare
Initiative, is published online in the Proceedings of the Royal Society B.
The study is the first to demonstrate that birds possess one of the
important attributes that underpins empathy, and the first study to use both
behavioural and physiological methods to measure these traits in birds.
Using a well-controlled experimental procedure and making use of
technical advances in non-invasive physiological monitoring, the researchers
found that domestic hens show a clear physiological and behavioural response
to their chicks' distress.
During one of the controlled procedures,
when the chicks were exposed to a puff of air, the hens' heart rate
increased and eye temperature decreased. The hens also changed their
behaviour, and reacted with increased alertness, decreased preening and
increased vocalisations directed to their chicks.
Some of these responses
have previously been used as indicators of an emotional response in animals.
In domestic chickens, time spent standing alert is associated with higher
levels of fear. Previous research carried out by the same group has shown
that hens also selectively avoid surroundings associated with high levels of
standing and low levels of preening.
Miss Jo Edgar, PhD student in
the School of Veterinary Sciences, said: "The extent to which animals are
affected by the distress of others is of high relevance to the welfare of
farm and laboratory animals.
"Our research has addressed the
fundamental question of whether birds have the capacity to show empathic
"We found that adult female birds possess at least one of
the essential underpinning attributes of 'empathy'; the ability to be
affected by, and share, the emotional state of another."
researchers used chickens as a model species because, under commercial
conditions, chickens will regularly encounter other chickens showing signs
of pain or distress due to routine husbandry practices or because of the
high levels of conditions such as bone fractures or leg disorders.