A few weeks ago I got an email asking this simple question: Do chickens smell?
Perhaps, incorrectly, I did not interpret the email as meaning, Does a flock of chickens create a nasty odor? Rather, I took it to mean Do chickens have a sense of smell?
Now that was an interesting question! There are many researchers currently investigating avian senses, and I’m sure that more details will come with that work. But for now I have a really interesting answer.
Up until recently it was the widely held assumption amongst experts that birds have only a rudimentary sense of smell. But, a few gutsy, out-of-the-box-thinking (mostly) women scientists have shaken that world view. (Read a good overview of that story and research here.) Not only can birds smell, but they rely on it more than once believed. There’s a lot of variation within avian species and so there is a wide spectrum of how sensitive each species’ sense of smell is, and how much they rely on it. It turns out that some birds that spend their lives soaring over the ocean find food by scent! That’s not the case with our domesticated chickens that have been selectively bred for traits other than sense of smell; chickens are not the animal kingdom’s best sniffers. Still, chickens can and do use smell to help make sense, and make decisions, about their world.
Chickens develop their sense of smell even before hatching. Chicks are able to smell from inside of their shells. In one experiment, eggs were rubbed with strawberry scent. When the chicks hatched, they preferred strawberry scented shavings and water. Adult chickens respond to scents, too. One researcher discovered that chickens respond with alertness when the feces of a prey animal (in this case, a tiger) was put into their pen. Droppings from non-prey animals did not affect the chickens. Another study showed that roosters respond to the scent from a female’s preening gland.
However, chickens do not use scent to make most of their decisions about what to eat or who to consort with. Sight and sound have far more influence. Partly this is due to the fact that taste and smell work in concert and a chicken’s sense of taste is not the most sensitive. A chicken has only a few dozen taste buds (compare that to a cow’s 25,000) and those buds are located well behind the front portion of the tongue which is cornfield (rough). By the time the food reaches the taste buds, the chicken is already committed to swallowing the morsel. They do not taste and spit out!
I have heard anecdotally about flocks that reject a change in feed. To our human noses, the change has to do with the sugar content – one bag smells sweetly of molasses and the new bag does not. Current research doesn’t support our human-centric view of what is going on. Chickens do not appear to respond to sugar. However, studies do show that chickens prefer corn over rye, so the chickens are objecting to something in the formulation, it’s just not the sugar! A researcher has also looked into flavorings marketed as appetite enhancers for commercial flocks and found no correlation between food consumption and these products.
We’ve been told that our backyard chickens self-regulate for things such as calcium and grit, and that they will seek out foods with nutrient content that’s optimum for them. It turns out that that is only somewhat true. Much more research needs to be done, but it appears that our hens are good at regulating some nutrients by selective eating, but not all. Also, they quickly become indifferent to what was originally offensive to them. What our chickens do care about is the temperature of their water! Research shows that they drink far less when the water is above their own body temperature. Cool water is a must. I’ve certainly noticed how much my flock appreciates fresh cool water, offered in the shade in the heat of the summer months. (On the flip side of this, if you think you’re indulging your hens by offering warm water and hot oatmeal in the winter think again.)
Perhaps this is more than you want to know! All you have to come away with is this – yes, chickens have a sense of smell and taste, and it does influence them somewhat, but, it’s still up to us to provide them with a balanced diet of healthy and nutritious feed. And, you don’t have to fuss over flavoring their supper.
This post is so ironic! I have been watching our hens behavior when it comes to smell. Our hens love raisins. I keep them in my duster pocket. On days I bring raisins, I give their usual fare table scraps, but the hens stay by the fencing waiting as if in anticipation. They pace back and forth and chatter. Totally different behavior on days I don’t have raisins. They dig right into the table scraps. The only thing I can conclude is that they smell the raisins. I wear a thick, wooly sweater over my duster, so I know they can’t see that I have them. I also read, may have been here, that chickens see color as we do. Do you know if this is true, Terry? Good post, makes one think.
I’m working on a color post :)
Not all chickens like raisins. Mine don’t. How they develop taste preferences is not yet fully understood, but the strawberry research is fascinating.
Chickens avoid citrus, and I think that smell plays a part in that aversion.
I found the article about Audobon really fascinating. Who would believe he didn’t know. Another example is when we had sand. The hens stayed out of the coop because of the poo odor. When we started using pine shavings, they spend a lot more time in there.
Most interesting post; you always provide the best, most practical information. I am surprised to read that chickens avoid citrus because my 4 girls(2 easter eggers, 1 black star, 1 australorp)devour oranges and grapefruit. I quarter the citrus and toss it in their run. They eat only the fleshy part leaving the membrane and rind.
I’m very glad that you brought up citrus! Mine have never touched it, but I shouldn’t have extrapolated to all flocks. There’s much erroneous information out there about feeding citrus to hens. LIke any food, too much of one is bad. But, it’s not true that citrus is toxic to chickens. In fact. around the world, citrus pulp is fed as part of rations.
Hmm, chickens must have a taste for something bitter, otherwise they would might posion themselves since most posionous but not all posionous things taste somewhat bitter. As for not tasting something sweet, I am suprised they can’t since they are omnivores. But then maybe it is only mammal omnivores and herbivores that can taste sweetness.
There are different components to sweet. Birds that rely on ripe fruit, like parrots, need to discern all of them, chickens don’t.
Buzzards find dead animal to eat by the smell on the wind. They have an incredible sense of smell.
Research shows that vultures are quite particular about how old the carcass should be to “taste just right” – and that they can smell it.
Did you know that nothing in nature that is sweet is poisonous. The main reason we are so hard wired to like it.
Twiggy looks so unimpressed.
Terry why do you think hens will gobble up scratch feed like it is their last meal but pick all days long at their laying pellets? Mine are so ticked at me in the morning when I put layer pellets in their feeder rather than scratch. They run in, look and run back out into the run.
I can’t imagine that the grain is any better tasting than the layer feed.
Well chickens have eyes too Ken. A good chef will tell you a meal has to look visually appealing as well as taste delicious. Pellets just look and smell blahh……. :)
The evidence isn’t yet clear about why chickens select some foods and not others. For some, it’s clear that somehow they know nutritional content – but this isn’t true for all foods. They do taste and smell, not like we do, but perhaps it’s enough for some selection. Their sight, of course, sees details that we don’t.
Ken my layer pellet feeder can be full, and the chickens will go stand near the garage door whereni keep the cracked corn…
And then there’s the excited chicken version of “Yes!” followed by the mad dash after anything that wiggles and squirms. :)
Yep. Their eyesight and what they react to, is very interesting!
Mine also dislike carrots ( the shredded pulp from the juicer)
Mine dont like carrots either
I have a hen who is particularly spoiled, and gets to come into the house now and then for special treats. I’ve noticed that since she is by herself, with no worry over another hen grabbing them, she’ll demonstrate clear taste. She’ll sometimes refuse to try things based on looks and/or smell, while others she’ll eat – but only after picking them up, rolling them around in her mouth, and spitting them out. She frequently vocalized her findings on the food while doing this, and once she’s decided she doesn’t like it, she won’t eat it again. If she likes it, I find that if I give her the same food too often in a row will make her refuse to eat it any more, even though she previously loved it. She’s a little gourmand, this hen! It made me realize how they really do taste their food! Her behavior is completely different while in the flock; then she just eats everything down quickly, so the other hens won’t get it first – even if it’s something that she won’t eat while alone, and a thing that I know she doesn’t actually care for. It’s quite fascinating to observe her. I’m always looking in the cupboards trying to come up with new things for her to taste.
Oh – and my hens must be weird. They like warm water in winter. I give them a free choice of cold water or warm water, and they cluster around the warm water and drink and drink and drink!
I’m not advocating icy cold water in winter :) My hens get lukewarm water because their dispensers are on heating pads to keep the water from freezing.
Great post. Loved it!
Uh oh! I’m guilty of huge bowls of warm oatmeal on wintry days, no kidding.
One night last summer I let the ladies out to free range where they had eaten off a watermelon rind the evening before. It was covered with Japanese beetles and June bugs this second evening. They were so curious. Most pecked then left, but a few stayed and pecked some more and it seemed to me they were pecking apart the nasty bugs in order to get at some good part inside. Too gross for me, though! I had to look away.
Today was the first day of little chicks at TSC. I resisted. I have eggs in the incubator!
It can take awhile for the chickens to learn which bugs they like, and some they never do.
I have chickens that won’t touch a worm. Throw one in the run, they’ll run over take a look and turn there nose up.
I’d be interested in research on what is learned behavior, and what is innate. Also, what role do mama hens play, and what happens to food decisions when chicks are raised in sterile brooders? All good, unanswered questions.
Yes, fascinating subject.
I have to add those same hens that won’t eat a worm I find and throw in the run will run over when I over turn some of the logs I keep in the run and grab the worm that is sticking it’s head or tail out, grab it and scarf it down.
I’ve raised Cornish cross in the past and around 4-5 weeks of age I’ve built a small out door run so they can get out in the fresh air and sunshine. There was grass in the run, they never touched it.
The meat birds can’t afford to eat empty calories – they need protein and bulk. Wonder if that’s why. Although I’ve also heard that they aren’t very bright :)
They have no “brightness” to them at all. I always found them very frustrating to work with.
The good news 8-12 weeks off to freezer camp they go.
Some of mine go crazy for worms. And 2 that wont touch them
I also think texture comes into it. My girls would eat as much mash as you give them but it’s just their pellets with water. They choose it over pellets though. Now and again I give plain live probiotic yogurt a as little now and then is supposed to be good for their digestive system and they go crazy for it, they would lick the bowl if they could. Their other favourite treats are tomato and grapes which will get chosen over other things and eaten instantly where as other things they like, such as cabbage and apple they will peck at over the course of the day. They go crazy when I dig worms for them and will chase each other for possession so it’s good excercise too. They love corn, meal worms and sunflower hearts equally but the quickest treat to disappear of all, is scrambled eggs made with a little olive oil and water as an occasional boost. I also found if I mixed limestone flour into their mash (when a new layer had a couple of soft shelled eggs) it didn’t go down as fast but when I switched to putting in ground eggshells instead it was wolfed down. I concluded that they didn’t mind the grit over powder. Sorry to go on so long. I do agree with smell and taste but just think texture also has a lot to do with their preferences.
I have a good friend that is a foreman at a plant that makes all types of pasta. Every other month or so he brings me a big box of pasta that was overruns, cut wrong etc. I appreciate it greatly but it’s always more than I can use so I boil it up and feed it to the hens. It is a comical sight. I don’t know if they think it is worms or little snakes, but they love it.
Speaking of snakes, chickens will eat them as well, not pretty.