Although the article only mentions some of the diseases that are prevalent in the back yard flock, it is a well written article with some great advice! A great read for all of us, those that have chickens for a bit and the new chickens owners...highly recommend!
http://www.hobbyfarms.com/livestock-and-pets/chicken-disease-prevention-basics.aspx
http://www.hobbyfarms.com/livestock-and-pets/chicken-disease-prevention-basics.aspx