commercially chickens are categorized as to whether ther are egg-type or meat-type bird. The White Leghorn was developed as an egg-laying type. it is a medium-sized breed that lacks the meatiness of the meat-type breeds. The meat breeds include the Plymouth Rock New Hampshire Cornish . No breed associations exist individual breeds as ther do for sheep cattle horses and swine. The American Standard of Perfection serves as a guide to the characteristics of the socalled purebred chickens. This document is published by the American Poultry Association.