Biology is founded on observational research. Pivotal insights about our world were the result of some guy needing a hobby, so he traveled to new places, peered through homemade lenses, or grew pea plants in a garden. The research environment may have changed drastically since their time, but observation remains a key factor in our scientific process. It’s that moment when we look at something and ask, why?

I experienced this moment firsthand while raising chickens in my backyard. As any chicken owner will tell you, caring for these animals is a full time job. Every morning I would begin my day outside, trudging across the dewy grass towards an indignant (but muffled) choir. The hens would quiet while I fumbled with the coop door, then they would burst out, eagerly greeting the day. While they busied themselves with breakfast, I would check the coop for eggs, adjust their fencing, then simply stand and watch them move about, on the alert for any abnormality in their behavior. If they passed inspection, I would return to the house for some human breakfast.

Throughout the day, if I wasn’t busy with something else, I was checking on my chickens. And this wasn’t paranoia alone – every passing instant in a hen’s life buzzes with potential energy. One moment they’d be calmly sunbathing, the next they were stalking a very agitated garter snake. Once they had grown big enough to clear the fence of their pen (in a frantic flapping leap), they made a habit of exploring the yard. I would glance out the window and see three red spots creeping through our blueberry bushes, or onto the neighbor’s property, and then it was a scramble to corral them. One morning, a hawk dove and got one of my hens while I was in the shower. I began to sit outside to work, guarding the remaining two closely.

I probably spent hundreds of hours observing chicken behavior that year alone. A great deal of that time involved some degree of interaction with the birds, from simple visual contact, to wrestling with a squirming hen as I applied antibiotics to her swollen earlobe (she gave bumblebees a wide berth after that). And just as often, my chickens were observing me.

I was the first living thing they saw every morning, and they arguably anticipated my arrival. Cues such as the sound of my footsteps and tired call of “good morning, chickies”, the sight of my figure approaching the coop through the window, would consistently come prior to the much-desired opening of the door. This is a classic example of classical conditioning (think Pavlov’s dogs), where animals learn to attribute meaning to a previously neutral, or meaningless, stimulus. Chickens are a very food-driven species (who isn’t!?), so beyond getting out of the small cramped space and into the fresh air, they likely associated my morning arrival with the promise of breakfast.

In fact, they probably formed a general association between me and food. Beyond the daily dish of layer feed and scattered chicken scratch, I found plenty of ways to enrich their diet throughout the day. Clover and dandelion leaves I collected on my afternoon walk. Sticky peaches from the tree in the front yard. Wilted lettuce and squishy grapes. On hot summer days, I would drop frozen berries in their water dish. On the coldest winter mornings, they got oatmeal with a little cinnamon mixed in. My chickens would run to the fence whenever they caught sight of me, even through the window of the house, and I almost always came bearing gifts.

But is that all there is between us? I’d ask myself as I watched them attack their newest treat with relish. Is their excitement because I am the food-bringer, and nothing more?

After another autumn hawk encounter, my hens bolted and hid in the forest, refusing to reemerge (again, I was in the shower!). My family searched, trying to coax them out with their favorite treat, scratch feed, but they sat still and stubborn for almost half an hour. It wasn’t until I made it outside, and they heard my voice calling, that they returned to the yard. This event got me thinking: food alone wasn’t enough to convince them. They came back because I was there. Perhaps there’s more to our relationship than I thought?

Months later, I was housesitting and caring for a flock of birds, a motley crew of Wyandotte chickens, Chinese geese and mallard ducks. My Rhode Island Reds stood out like a sore thumb amidst the other black and white hens. These other birds tolerated my presence (after all, I brought breakfast), but my hens were noticeably warmer towards me. When the weather was nice, my partner and I enjoyed daily walks up the road, taking advantage of the upstate mountain paths. It was without fail that upon our return to the house, two spots of red would emerge from the grass and race towards us, trilling delightedly.

One day, a dog ran into the yard, romped briefly among the terrified birds, then raced away into the woods. Luckily it meant no harm, but who was going to tell the hens that? By the time I had made it outside, every black and white chicken had made a beeline for the nearest goose. My two hens had meanwhile disappeared once more into the brush. For the remainder of the afternoon, the black and whites clustered tightly around the geese. Geese are protective by nature, it was obvious that they considered the smaller birds part of their flock (from their initial aggression towards my chickens, and their boisterous honking at passerby). But this event appeared to demonstrate a reciprocal behavior: the black and whites considered the bigger birds their protectors.

Almost a year later, I’m sitting in my thesis advisor’s office in Linköping, Sweden. On the subject of interspecies relationships, I told him the dog story. “Really?” he said with raised eyebrows. “I’ve never heard of that.”

I was surprised. After all, he’s the chicken expert. I’d sort of assumed it was a given that chickens could form relationships with other species…there are countless online accounts of chickens befriending geese, dogs, even people. However, there isn’t a speck of science backing these claims. Trust me, I’ve looked. The closest thing I’ve been able to find is a brief note published in a 1944 publication of The Auk (today titled Ornithology), “Observations of interspecific sexual behavior between a chicken and a pigeon”, in which Howard H. Vogel Jr. described a male pigeon’s sexual advances on a hen, housed together on the Wabash College campus. An amusing find, sure, but can that really be all there is?

The lack of research makes some sense. Chickens are housed in isolation from other species in commercial facilities, where even human contact is limited by the use of automated systems. While privately owned flocks may sometimes resemble the assorted group I cared for while housesitting, more often than not, risks such as avian flu encourage backyard chicken owners to house the birds separately from other animals. So, when you think about it, I had the opportunity to observe a relatively novel circumstance: a group of chickens that was raised alongside geese, and a group of chickens who were more recently introduced to the same geese, were together exposed to a predator stimulus. I saw a stark difference between each group’s behavioral response which was directly related to their level of familiarity with the geese.

So what to do with this information? I may have taken the most eccentric approach…after finding the published data lacking, I traveled to Sweden to attend a master’s program so that I could conduct the research myself. Don’t worry, you can laugh. But that’s how I got here, armed with the question: do chickens form relationships with humans?