Two dwarf brown-egg layer lines, differing in their genotype for the naked neck gene (NA), line L2 (NA*NA/*NA) and line L1 (NA*N/*N), have been selected for 16 generations for increased average clutch length. A control line from the same base population, dwarf and segregating for the NA gene, was maintained by random mating. Genetic parameters were estimated by a multivariate derivative-free re...

Three White Leghorn strains, their two-way crosses, and two commercial lines were used to study the effects of aging on several parameters related to performance of fitness and nonfitness traits during the first laying cycle of hens housed three per cage. Egg number of the survivors (EPF) and egg number including mortality and morbidity (EPM) were divided into 12 periods of 28 d each, starting ...

A mapping population segregating for egg quality traits was created by a line cross between two egg layer lines and screened by a genome scan. The F2 generation consisted of 307 hens, which were scored for egg quality and production traits. The mapping population was genotyped for 99 microsatellite loci, spanning nine macrochromosomes and five small linkage groups. The linkage maps were used in...

Complete egg production data from a pair breeding flock located in South Africa were used to generate annual reproductive records for all hens exposed to breeding. Traits analysed included measures of total egg and chick production and related traits, along with egg and chick weights. Both genetic and non-genetic factors significantly influenced reproductive performance. Seasonal effects, durat...

this experiment was conducted to evaluate the effects of using rice bran, combo multi-enzyme and probiotic (protexin) in diet on performance, egg traits, biochemical parameters and blood cells of commercial laying hens. this experiment carried out using 384 hi-line (w36) laying hens in a completely randomized design as factorial (2×2×2) arrangement with two levels of rice bran (0 and 10%), two ...

An experiment was conducted to evaluate the effects of different levels of licorice powder (LP) in diet on performance, egg traits and some serum biochemical parameters of laying hens in the late laying period. Totally 180 Hy-Line W-36 layer hens aged 55-68 weeks with similar weight were selected and assigned to 5 treatments, 3 replicates and 12 hens in each replicate in a completely randomized...

481 fresh fertilized eggs of three Kurdish local chickens (Black with brown neck, White with shank feathering, and White with non-feathering shank) were collected at pre-molting (355 eggs) and post-molting (126 eggs) stages to evaluate external egg traits. A venine caliper was used to determine the length and breadth of eggs to calculate Shape index. Results indicated that egg weight increased ...

in this experiment 180 azerbaijan province native laying hens from 28 to 40 weeks were separated in 6 treatments and 3 replicates (10 birds per replicate) as a (2 × 3) factorial arrangement of treatments in a completely randomized design. treatments included two levels of dried tomato pomace (dtp) (8 and 16%) and 3 types of using methods (unprocessed, alkali and acid processed). the results sho...

this experiment was conducted to evaluate the effects of different levels of costmary(tanacetum balsamita)medicinal plant on performance, egg traits, and blood biochemical parameters of laying hens. hundred-eighty of hi-line laying hens (w 36) from 46 until 58 weeks of age were used in a completely randomized design in five treatments and three replicates (12 birds per replicate). the treatment...

Iranian native hens are a valuable genetic resource, due to their adaptability to harsh conditions of husbandry and environment in rural area. The genetic parameters for various traits of economic importance were studied in an Iranian Native chicken population under short term selection for egg production and body weight for over 2 years. The parameters studied were body weight at day old (BW1)...