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Sounds, body language and facial expressions are used to communicate emotions by mammals like pigs, dogs and mice.
A new study by a team of French researchers has found that chickens are highly expressive animals with a lot to say. The researchers found that hens blush and fluff the feathers on their heads to express various levels of excitement and emotion.
“For now, we are at a preliminary stage where we have been able to describe rapid color changes on the hens’ faces and movements of the feathers on the top of their heads. We observed a gradation in the intensity of redness across the face depending on the emotions we studied. The lightest shade is observed in calm contexts, while the darkest shade appears in negative emotions, such as fear, which can be triggered by the sight of a predator in the sky, for example. The feathers can be sleeked or fluffed, and they are most often observed fluffed in contexts with positive emotional valence,” Aline Bertin, co-author of the study and a scientist with the French National Research Institute for Agriculture, Food and the Environment (INRA), told EcoWatch in an email.
The researchers filmed 18 chickens — all domestic females (Gallus gallus domesticus) of two breeds — performing everyday behaviors on a farm in France, a press release from the Public Library of Science said. Additionally, they filmed the chickens being held by a human, as well as receiving an enticing food reward.
The research team analyzed the position of the birds’ facial feathers as well as the color of their exposed facial skin in seven contexts that varied in level of excitement and degree of emotion. For instance, when hens are content and relaxed, they preen their feathers. They get excited and happy when they are given a food reward, but being captured is both exciting and scary.
The results of the observations suggested that head feather position and skin color variation change depending on the situation. The team found that the fluffing of head feathers was mostly associated with a contented state, while blushing indicated excitement or fear.
“The skin blushing on the face of the domestic fowl is a window into their emotions. The intensity of the blushing varies within a few seconds depending on the emotional situations they experience,” the study’s authors said in the press release.
Hens’ skin tended to be redder in exciting contexts, as well as those that produced negative emotions. Under circumstances that brought about both a positive emotion and excitement, the chickens showed intermediate skin redness, which the researchers concluded indicated a blushing continuum of subtle emotional changes.
So do hens have any ways of expressing their emotions other than fluffing their feathers and blushing?
“Yes, they do have other ways to express their emotions. Like mammals, hens also have body language. For example, when they are on alert, they will stop their activity, adopt a specific posture with their heads held high, and observe their surroundings,” Bertin told EcoWatch. “Hens also have a vocal repertoire that can signal positive or negative emotions. They can emit alarm calls or signal the presence of appetizing food. One of the challenges in a group is identifying which individual is the source of the vocalization. Additionally, hens do not necessarily vocalize in all contexts. For instance, when they are very frightened, they may freeze completely and not make any sounds. They are also relatively quiet when they are in a calm state.”
Bertin said the frequency with which hens express their emotions depends on the environment.
“An emotion corresponds to a brief psychological response following a positive or negative stimulus from the environment. For positive emotions, we might think that a hen living in an enriched environment (such as an orchard) would have the opportunity to experience positive events several times a day, like chasing insects, eating fruit, or enjoying loose soil for dust baths. However, such an environment does not protect them from negative emotions,” Bertin explained. “They can become alert in response to sudden noises or the presence of predators.”
Bertin said how important facial expressions are in social interactions between hens is still under investigation.
“The question of whether the expression of emotions plays a role in the functioning of social groups is very interesting. One of our goals is to try to describe facial expressions during encounters between familiar and unfamiliar hens, as well as the associated behaviors. We are also trying to determine if they react in a particular way to images that show contrasting expressions. We might speculate that, as with mammals, facial expressions play a role in approach-avoidance behaviors within groups, but this remains to be determined,” Bertin told EcoWatch.
Bertin emphasized that chickens are definitely social animals.
“When they have the opportunity to live in small groups, social cohesion is maintained through the establishment of dominance-subordination relationships between each of the individuals. Once the hierarchy is established, each hen knows her place. When a rooster is present, he will hold the highest position in the hierarchy,” Bertin said.
How many of the hens’ facial expressions have the researchers been able to identify?
“It is a bit premature to try to quantify the number of possible expressions. Anecdotally, we have observed much more extreme feather movements, but observations of free-ranging animals do not always allow us to track all events in the environment and gather sufficient data. We would also need to include the movements of the neck feathers and study the dynamics of color changes depending on different areas of the face. For example, if you watch the short video attached to the article, you will see that the hen blushes around the wattle (under the beak) and around the eye, but not around the earlobe (near the ear). We are just at the stage of showing that hens have the ability to modify different aspects of their faces, but we cannot yet establish a true repertoire of all the possible combinations,” Bertin told EcoWatch.
The study was the first to examine the emotional facial expressions of hens. Bertin said the findings could help improve the welfare of chickens living on farms.
“Empirically, skin color is already used to assess, for example, the health of birds. Sick birds will have white or even bluish skin over the long term that does not change color even when the animal is stimulated. The crest will also be paler. With a bit of training, I believe the rapid color changes we describe (as illustrated in the video included in the article) can be perceived by the human eye. Skin color could, for example, be used to evaluate the quality of the human-animal relationship,” Bertin said. “Fearful animals will maintain a distance from humans but also have redder skin. We can also think that states of calm could be more easily identified by lighter skin and slightly ruffled head feathers. This could be useful, for example, in better assessing these states when environmental enrichment procedures are tested. States of calm are important to consider for animal welfare, but they remain very difficult to infer objectively.”
Bertin said the way humans perceive animals is essential to prioritizing their welfare.
“I also believe that our work can change the way we view these animals, who are often overlooked. Taking a more interested and respectful view of an animal is an essential first step that can lead to changes in our consumption choices,” Bertin told EcoWatch.
To improve the welfare of animals, there are steps we can take as a society to build a consciousness around the complexity of their lives that is currently lacking.
“I sometimes think that knowledge about animal life and the richness of their mental lives should be introduced much earlier in schools. This would likely improve the way we interact with all animals that depend on us (including our pets),” Bertin said. “As for the welfare of hens, there have already been some advances, such as the reduction of cage farming for laying hens. This demonstrates that as consumers, our choices can play a key role in the evolution of farming systems.”
Profiles of a hen showing different feather positions and skin redness, and the four regions of interest where redness was sampled. PLOS
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