Phenotypic characterisation of local-exotic naked neck crossbred and normal feathered chicken population

Abstract

Phenotypic characterization of two phenotypes (normal feathered and naked neck) and two lines (white and brown) of local-exotic crossbred layer chickens was undertaken at 22 and 36 weeks of age. A total of 240 birds were randomly selected for the experiment. The sample comprised 120 males and 120 females with 60 birds per line (brown and white) and 30 birds per phenotype per line (naked neck and normal feathered). Data were collected twice at 22 weeks (during the period of sexual maturity) and at 36 weeks (peak performance). Qualitative traits (eye colour, comb type, comb colour, ear lobe colour, plumage colour, beak colour and shank colour), body weight (BW), and morphometric traits namely body width (BWd), body length (BL), shank length (SL), shank circumference (SC), comb length (CL) and wattle length (WL) were measured. Data on BW and morphometric traits were subjected to ANOVA and descriptive analysis was used for the qualitative traits assessed. Male chickens had significantly (p<0.05) heavier BW and higher morphometric traits than the females at both 22 and 36 weeks of age. This is because higher is preferred to heavi-er in describing morphometric traits. Chicken line has significant (p<0.05) effect on BW and BWd at 22 weeks and BL and SC at 36 weeks. Chicken phenotype also significantly (p<0.05) influenced BWd and SL at 22 weeks and BL, SL and SC at 36 weeks. Important interactions of sex, line and phenotype also exist for some of the morphometric traits. For the qualitative traits, the predomi-nant comb type, comb colour, earlobe colour and eye colour were single comb (100%), red (76%), red (90%) and orange (82%), respectively. Body plumage was either white or brown for both lines. In conclusion, this study highlighted the phenotypic diversity within the local-exotic crossbred ge-netic resource.