look up the Chicken Chicks website it has all the best studies ever done for chickens you’ll learn a lot there!
The Chicken Chick website has quite a few articles, with nice pictures, but I would not trust the information without checking other sources. Some of it is right, but some is wrong, and unless you already know the material it can be hard to tell which is which. (Some of the wrong parts are from the experts that get interviewed, while some of the wrong parts are from the author herself, so that's not consistent either.)