ABSTRACT

The thermoregulatory effect as well as productive adaptability potentials of the naked neck and frizzle genes found in some genotypes of the tropical chicken has been reported by researchers like, Horst (1988, 1989), Ibe (1993), Nwachukwu el al. (2006). Opinions are consistent among investigators that birds possessing naked neck and frizzle genes tolerate thermal stress better than t11eir normal feathered counterparts, with such birds manifesting evidence of productive adaptability. Productive adaptability itself is a phenomenon whereby an animal gives acceptable level of production in a stressed environment. The tropical environment is generally characterized by such stress factors such as excessive heat, poor nutrition, poor housing and diseases. Attempts to significantly reduce heat stress problems in poultry through management practices or dietary adjustments have not been successful. Mathur and Horst (1990) reported the superiority of individuals with frizzle and naked neck genes both singly and in combination over individual with normal feathering for body weight and eggs traits. Eberhart and Washburn (1993) reported a genetic basis to heat resistance and suggested the need to breed birds with more natural resistance to heat. A tendency for reduced body weight for birds that were genetic more resistant to heat stress. In order to utilize these characteristic of the naked neck and frizzle genes, and exploit heterosis to evolve a more productive, resistant and productive hybrid chicken, cross-breeding tool has been considered a desirable breeding method for upgrading the local chicken with suitable exotic ones. The exploitation of local poultry genetic resources for improving economic traits, such as body weight which is one of the most important traits in poultry is a cherished breeding goal.