Mark Twain wrote that “Man is the only animal that blushes – or needs to”. New research seems to have proved him wrong, however, with the discovery that hens have the capacity to blush and use other forms of facial expression.
Researchers in France found that female chickens appear to blush when they are scared or excited and fluff up their head feathers when they are content. The finding offers a new way of understanding the birds’ emotions, which could help farmers judge the happiness of their flock.
Facial expressions are an important method by which humans communicate emotions, and research has shown that other mammals – including mice, dogs, cats and pigs – use them to varying degrees. Aline Bertin, a senior author on the latest study at the French National Research Institute for Agriculture, Food and the Environment, said she hoped the research would provide similar insights into birds.
“The emotional world of birds remains largely unexplored compared to that of mammals,” she said. “We aimed to determine if facial markers of emotions could also be detected in birds, with the ultimate goal of better understanding and considering their emotional capacities.”
In the study, published in Plos One, researchers filmed the behaviour of two groups of hens – 10 reared on a commercial farm and eight kept by a private breeder – during situations that caused differing emotional responses and levels of excitement. For example, being rewarded with food was seen as positive and stimulating, whereas being picked up and held by an experimenter was associated with being excited but fearful.
By analysing the footage, the team found that the exposed skin on the hens’ faces reddened when they were scared or animated, such as when they were picked up by a human or heard a noise they perceived as a threat. The birds also tended to spike up their head feathers when they were relaxed, such as when preening themselves or resting.
There are few ways to reliably assess bird emotions and this is the first time blushing has been linked to hens’ moods. The authors suggest that farmers hoping to improve the welfare of their flock may wish to aim for the relaxed, happy state indicated by low redness and spiked head feathers.
Dr Paul Rose, who studies animal behaviour at the University of Exeter, said the findings could lead to happier hens. “To improve how we assess animal welfare in industry, quick, easy and reliable indicators are key,” he said. “The authors seem to have discovered some, especially with the feather fluffing, which I think would be easy for animal care staff or farmers to observe and identify as something that could suggest their birds were content.”
