Not only do they have better colour vision, they have MUCH, MUCH, MUCH better colour vision; All birds do. While it is sometimes referred to as seeing in additional dimensions, they have more types of light receptors than we do, and these receptors are more densely packed in their retinas. The spectrum of lght they see is considerably wider than that of humans. Birds see into the UV portion of the spectrum, and can distinuish differences in the wavelength of light that the human eye is incapable of distinguishing.
Most birds also have much better resolution than mammals: for example, raptors flying at high altitude can make out the details of a small rodent on the ground. Not quite sure of the lens capabilities of chickens, but I would speculate that it is better than that of the average human with no vision issues.
What birds do not have is a good sense of smell (there are a couple of exceptions: scavenger birds have a good sense of smell).