The science behind a chicken’s eyes

Recent scientific discoveries have shown that chickens eye sight is better than that of mammals (humans included) in terms of colour. A chickens retina (light sensitive structure) is organized in a complicated structure of interwoven mosaics, and the cones (colour sensitive) can detect colour spectrum that human’s cannot. While humans can detect red, green and blue wavelengths, most birds (chickens included) have receptors for red, blue, green, violet and ultraviolet meaning that they may see an entirely different dimension.. Where a human would see green dots, a chicken would see different coloured dots, depending on the varying amounts of ultraviolet light.
When light enters the eye through the pupil which expands and contracts to allow sufficient light through, it travels through the lens and is reflected at the retina .The chickens retina can detect not only detect some ultraviolet wavelengths but also has special motion sensors which allow them to see motion in a way that we do not truly understand.
If a chickens eye is viewed side on, you will see that they have a transparent ‘bulge’. This is called the cornea. Did you know that chickens have eyelids? Three infact. They have a nictitating membrane, which is between the other eyelids. It slides sideways over the cornea and cleans and protects the cornea with lubricating fluid from a duct that serves the same purpose as our tears. their bottom eyelid moves up to meet the top one when they close their eyes, but they only close these eyelids when they are sleeping.

If you like science subjects, why not look at our Chicken genetics page and our The Science and Anatomy of an egg page, or browse our The Science of Chickens category.