Blushing Chickens
When I come across a study that reveals a way to understand what animals are feeling, I get excited. I suppose that excitement is a large part of why I write these posts; it feels good to share it with you all. When the animals happen to be chickens, I’m extra excited.
Many people know me as a primatologist and find this fascination with chickens bizarre. Granted, many of these people have just walked into my office and seen coasters with chickens, stuffed animals that look like chickens, and some small chicken figurines.
I tell them that chickens are refreshing! Chickens tell it like it is. If they like something, they walk toward it. If they don’t, they walk away. And unlike primates, the layers of subtlety that obfuscate social relationships are stripped away. Chicken relationships are clear in their literal pecking order. They follow the rules learned in Animal Behavior 101. And, the way they walk makes me smile.
Looking for changes in chicken faces
So when I came across a study claiming that chickens have facial expressions that reveal their emotions, I was eager to give it a read. I immediately pictured a chicken’s face and thought, what changes are detectable on those tiny little heads?
The authors didn’t measure muscle changes that are typically considered in studies of facial expressions. Instead they measured changes in the redness of the chickens’ faces and changes in the height of their head feathers as the chickens were in different situations. The situations differed by whether the chicken likely felt good or bad, and by whether the situation was exciting or calming. These two characteristics are referred to as “valence” and “arousal” and according to the leading models of emotions, all animal emotions (including ours) can be mapped along these two dimensions.
(a) The red arrows show the areas of the face where the authors recorded redness. (b) The blue box indicates the feathers that were measured as either relaxed, as shown here, or upright. Image adapted from Arnould, C., et al. (2024). PLOS One, 19(7), e0306601.
Chicken reveal their feelings by blushing
Mark Twain said (I think), “Man is the only animal that blushes — or needs to.” Nope! The authors found that when chickens were in excited, or high-arousal situations, their faces were redder. This happened whether the arousal felt good, for example, when eating a pile of mealworms, or felt bad, for example, when being captured and held. In a sense, the chickens revealed their excitement through blushing, much as humans do. The mechanism is assumed to be changes in blood flow in the chickens just as it is in us.
The feathers were not as reliable. The authors found that the head feathers were more upright when the chickens were in positively valenced situations, or those that felt good. However, these situations involved chickens preening their feathers and dust bathing, which necessitates feather fluffing. So, I’d say the jury is still out on what head feather height can reveal.
We know that chickens have preferences, and that levels of arousal can be revealed through subtle changes in appearance and posture in other species. This study adds a new and exciting piece of information, namely that a change in chicken facial coloration can tell us something about how excited they are. Given that most studies of emotions have focused on mammals, it’s exciting to see this discovery for birds.
If you have chickens, what do you think? Do you notice their faces redden when you feed them, or when they are scared? If so, could you use this information to discern how they feel about something less obvious, like a new person or a different food? Something to try, perhaps!
Learn More
Read the original study. Arnould, C. et al. (2024). Facial blushing and feather fluffing are indicators of emotions in domestic fowl (Gallus gallus domesticus). PLOS One, 19(7), e0306601. Link to article.
Read about how blushing reveals our own emotions in this article.