The Haynes chicken manual was my bible when I first purchased hens. With no idea where to start or what was required this was great. It gives daily, weekly, monthly and seasonal tasks to keeping them happy and healthy, which I followed to the letter until I could make choices on my own hens needs.
It has help in choosing what you want right through to hatching eggs and dispatching and dressing surplus which I vowed I'd never need. Then 2 years on was sooooo glad for the detailed pictures and chapters.
River cottage handbook 11. Chicken and eggs, is also a very good book which I still read along with the Haynes. It goes into more detail of finding your own needs and gives in depth information so you can follow your chicken keeping path.