Have you ever been enjoying time with your chickens and watched as they seemingly reacted to something you were unable to see? Did this make you wonder about how both their vision and perception works? A lot of times animals both see and perceive things differently than humans do, so what looks a certain way to you can look much different to them.
While both humans and chickens can see well during daylight hours, humans have much better vision after dark than chickens do. Since chickens roost at night and have never been known to be nocturnal animals, they never had a reason to adapt and evolve to develop night vision. This could play a large role in chickens who raise the alarm flag at night for seemingly no reason at times; they cannot see well enough to know if a threat is present, so they make a fuss just in case.
Chickens have the ability to see in color thanks to possessing three cones in the colors of yellow, blue, and red. These cones enable chickens as well as humans to see a wide range of colors. In addition to these cones, however, chickens also have another cone that enables them to see ultra-violet light (UV). This comes in handy when scratching about for bugs as some bugs have exoskeletons that reflect UV light. Also known to reflect UV light are certain seeds and fruits as well as the feathers of baby chicks. The latter is beneficial as it alerts hens to which of her babies are developing on schedule and which might be lagging behind, needing extra attention from her. Chickens are also more sensitive to light as a whole be it UV or otherwise thanks to the pineal gland in their brains which senses the presence or absence of light.
While the eyelids of both chickens and humans may appear much the same, chickens also have a third eyelid. This is known as a nictating membrane and operates via horizontal movement to help keep dirt and debris out of the eye. Since this eyelid is mostly transparent, you may or may not notice its presence, but rest assured it is in use during activities such as dust bathing.
The eyes of a chicken are much larger relative to the size of their heads than that of a human. They also have a much larger field of vision due to the placement of their eyes on the side of their heads as opposed to the front like a person. This essentially gives them double the field of vision that we have. As if the awesome field of vision was not impressive enough, the eyes of a chicken have the capability to detect motion as well, often on such a small scale that they will notice a bug moving through the grass that a human being may never know was even there.
Based on the way chickens develop in the egg, they end up with a right eye that is nearsighted while their left eye is farsighted. As a result of this, you may notice your chickens tilt their heads when looking at something. They can also use each of these eyes independently so the head tilt will depend on the location of the item they wish to see, be it close or far.
Next time your chickens appear to be gazing at something of interest to them that you do not see, perhaps you will not be surprised knowing that chickens have a far superior eye. What they see and how they see it is beyond the comprehension and grasp of the human eye, so when your chickens act as if they have something of concern or excitement in their sights, you will just have to take their word for it. After all, when it comes to the appearance of frightening threats or delicious snack bugs, a chicken\'s eye will not lie!