CHAPTER ONE INTRODUCTION 1.1. Background of study Genetic improvement can take many forms, but it must follow an ordered hierarchy of events which starts from understanding of production and marketing system, choice of appropriate breeds or strain that can sometimes lead to replacements of existing breeds. (Nimbkar, et al., 2008). Reports have shown that feathers play an important role in broilers production especially during feathering processes (Omeje, et al., 1998). This is because they are made up of the same protein structure as human hair, keratin, though not uniformly distributed throughout the bird’s body as described by (Wilson et al., 2007). Rather they are arranged in rows to produce distinct feather tracts. Each tract follows a specific arrangement with distinct angles which give broilers a common pattern in feather. About 75% of a bird’s skin surface is covered with feather tracts with the uncovered areas being mostly beneath the wings and on parts of the breast. The follicles are formed during embryo development and fixed once the chick is hatched. During broilers life time each bird undergoes two molts. The first occurs during the first two weeks of age where the down feathers are mostly shed and replaced with juvenile feathers and the second at about 4-5 weeks of age where new feathers push the first set of feathers out (Bacon et al., 2005). The head and neck of broilers are the last area of the body to go through molt. It is normal to see broilers with first set of down feathers still on their neck and head area at 5-6 weeks of age. In adult birds, feathers are used for courtship displays and their pattern of structure also in sex differentiation of broilers. Contour feathers protect the broilers against the sun, wind, rain and injury in range type settings. In more industrialized settings with control environments, contour feathers protect broilers against scratches that could result in infection or bruising of the tissues. Down feathers make it possible to trap air insulating layer next to the skin providing much needed protection against heat or cold. Filopumes are thought to have a sensory mechanism that enables them to respond to air flow and direction of body feathers (Wilson et al., 2007).