Abstract
For phenotypic characterization, data on different morphological traits of 249 indigenous
chickens (ICs) from four villages of Sherpur district in Bangladesh were collected. Most of them
were single combed (99.20%) and non-descript Deshi (85.94%). The prominent colors of
plumage, shank and foot, skin, comb, earlobe, eggshell and eye were multiple (25.70%), white
(51.81%), white (88.35%), red (97.19%), white and red (58.23%), white (63.59%) and black
(99.60%), respectively. Back length, keel length and body weight of cocks and body
circumference of cockerels were significant. Body weight of hens and cocks were 1100.00 ± 69.18
and 990.86 ± 11.46 g, respectively. Strong significant positive correlation between body weights
with other body measurements were found while strong significant antagonism between shank
length and pelvis width was noticed, indicating that selection for one trait may affect the other
trait negatively. For genetic characterization, a total of 191 blood samples of ICs were collected
and analyzed using 20 microsatellite markers. A total of 218 alleles were observed with a mean
of 10.90±1.14 per locus and the mean polymorphic information content was 0.667±0.023 per
locus. The mean observed and expected heterozygosities were 0.654±0.027 and 0.708±0.023,
respectively. Analysis of Molecular Variance (AMOVA) revealed that 91.43% genetic diversity
was accounted for within population variation and the mean inbreeding coefficient was
0.087±0.019. The ICs displayed high level of genetic diversity indicating opportunity for their
improvement in situ. Data were collected on age at sexual maturity (ASM), body weight at
sexual maturity (BWM), body weight at one year of age (BWY), eggs per clutch (EGC), clutches
per year (CLY), hatchability on eggs set basis (HAT) and survivability (SUR) from a total of 1392
birds of three generations (Go, G1 and G2) from December 2010 to June 2013 measured to study
the effect of three breeding strategies (BS). At G2, ASM of female birds under BS₁
(168.50±1.12days) was slightly earlier than those under BS2 (169.63±1.05 days), suggesting BS, to
be more effective than BS2 in reducing ASM. BWM and BWY of male (1200.00±19.99;
1779.63±27.20 g) and female (994.48±10.86; 1350.38±14.46 g) birds in G2 were higher under BS2
than those of birds under BSi and BS3. EGC and CLY in G₂ under BS, (14.97±0.20 рc; 4.53±0.05
nos.) were higher than BS2 and BS3. However, in G2 the highest HAT (89.79±0.96%) was observed
in BS, but the highest SUR (51.15±2.36%) was observed in BS3. The results revealed that BS
would increase egg production and hatchability but decrease ASM of female birds while BS2
would improve body weight in rural low input system. Estimated heritabilities of ASM, BWM,
BWY, EGC and CLY were 0.50±0.02, 0.23±0.12, 0.15±0.10, 0.27±0.13 and 0.39+0.09, respectively.
Estimated values of phenotypic and genetic correlations between traits were variable (high,
medium and low) and were in positive or negative scales. The estimated genetic correlations
indicated that selection of birds with high BWM and BWY would lead to delayed sexual
maturity while selection of birds at the age of sexual maturity with high body weight would
increase body weight at one year of age. Among 64 top ranked male birds, maximum males
(37.50%) were in BS2 followed by BS, (35.94%) and BS3 (25.56%); among 186 top ranked female
birds, maximum females (39.25%) were in BS₂ followed by BS, (31.18%) and BS3 (29.57%). These
results indicated that using superior indigenous cocks and hens (BS2) on the basis of ASM,
BWM, BWY, EGC and CLY would be effective to improve the indigenous chickens of
Bangladesh in-situ. Genetic and phenotypic variation existed in the ICs and improvement in
productivity (both at genetic and phenotypic levels) was possible through employing
appropriate breeding strategy.