Apparently, Chi ckens have better color vision than humans:
Scientists mapped five types of light receptors in the chicken’s eye. They discovered the receptors were laid out in interwoven mosaics that maximized the chicken’s ability to see many colors in any given part of the retina, the light-sensing structure at the back of the eye.
“Based on this analysis, birds have clearly one-upped us in several ways in terms of color vision,” says Joseph C. Corbo, M.D., Ph.D., senior author and assistant professor of pathology and immunology and of genetics. “Color receptor organization in the chicken retina greatly exceeds that seen in most other retinas and certainly that in most mammalian retinas.”
The Science Daily article reports on this PLoS One paper – which is really quite interesting and applies to avians in general. Birds have five types of cone photoreceptors and the paper examines the way they are distributed in the retina. I’m still in the process of reading the PLoS paper, which looks quite interesting, so I can only say that I hope the chickens don’t team up with the cows!