Chickens have miniature color photography outfits in their eyes. This was what Dr. George Wald, instructor in Biology, said in an interview when speaking about his research in the field of visional Chemistry.
Eyes have two small types of elements on the retina, rods and cones. The rods are used in half light or in darkness, while the cones are used in color vision. It has already been known that there is a visional purple partly composed of vitamin A, which is used in seeing with the rods; it is this that has led to the recent research into the connection between night blindness and vitamin A.
This new pigment operates in one type of cone on the retina of the chicken's eye. In this one type of cone it has been found that the color filters and photosensitive substance are present making it a miniature color camera.