ABSTRACT

A total of 181 day - old crossbred local chickens were generated from a main and reciprocal crossing of local chickens possessing plumage reducing genes (naked neck - Na and frizzle - F) and normal feathered gene - na to evaluate their growth and early lay characteristics. The genetic groups produced were homozygous naked neck (Na/Na) and frizzle (F/F), heterozygous naked neck (Na/na) and frizzle (F/na) reciprocal naked neck (Na/F) and frizzle (F/Na) and normal feathered (na/na) chickens. The experiment was conducted in a randomized complete block design with genetic group as treatment and hatch as block. Results show that the F/F had significantly (P< 0.05) highest mean day- old weight (30.90 ± 2.73g), highest mean body weight at weeks 16 (442.50 ± 6.61g) and 24 (114.00 ± 32.99g) and showed highest significant growth rate (51.80) compared to those of Na/Na (40.45), Na/F (20.07), Na/na (35.08), F/Na (42.37), F/na (40.23) and na/na (35.55). There was significant difference (P<0.05) in mean daily feed intake at week 8, with the Na/F consuming 34.20 ± 1.74g. Mean body weight gain and feed conversion ratio did not differ among all the genetic groups. The na/na individuals survived most and had significantly least mortality of 24.00 ± 11.22 compared to other groups. Except for feed per hen, feed per dozen egg and percentage hen-day production which did not differ significantly among the egg production parameters evaluated, significant differences (P<0.05) were observed in weight at first egg, age at sexual maturity, age at 50% rate of lay, weight of first egg and egg number at 56 days, with greatest values favouring F/F (1299.00 ± 5.03g), Na/Na (177.60 ± 6.60 days), Na/na (191.00 ± 0.00 days), F/F (38.22 ± 0.70g) and Na/Na; Na/na (38.02 ± 7.88; 32.75 ± 5.27) respectively. Highest significant values of egg weight (EWT), egg length, egg index and shell thickness favoured F/F and Na/F (40.02 ± 0.45g; 38.70 ± 0.69g) F/F (50.32 ± 0.33mm), F/Na (0.84 ± 0.05) and F/F (0.92 ± 0.01mm), respectively. Highest significant means of yolk weight (YWT), yolk height, yolk width and yolk index were obtained from F/F; Na/F; Na/Na and F/Na (13.11 ± O.26g; 12.90 ± 0.24g; 12.74 O.24g; 12.68 ± 0.31g), F/Na; Na/Na; (13.29 ± 0.30mm; 13.24± 023mm) F/F; Na/F (38.01 ± 0.47mm; 37.40± 0.43) and F/Na; Na/Na ( 039 ± 0.01; 0.37 ± 0.01), respectively. There were no significant differences in albumen weight (AWT), albumen height (All) and Haugh unit (HU). However, HU values were very high in all the genetic groups. Highest positive significant correlations among EWT, YWT, AWT, AH and HI] were obtained in Na/Na, Na/F and F/na. It was concluded that the Na and F genes in the main crosses should be selected for the improvement of egg- and meat — type chickens respectively. Reciprocal crossing of Na and F genes can be exploited for the development of dual-purpose chickens. F and Na genes when combined like in F/na, Na/Na and Na/F genetic groups will be usethl in improving egg quality.