Not sure if this has been posted, searched and did not find it, but something I ran up on. If this should be posted else where please re-direct the post. Was not sure where it should go, but thought in was good information.
http://cal.vet.upenn.edu/projects/poultry/Syllabus/page37_44.htm
http://cal.vet.upenn.edu/projects/poultry/Syllabus/page37_44.htm