The general lack of experimental evidence for strong, positive effects of egg size on offspring phenotype has led to suggestions that avian egg size is a neutral trait. To better understand the functional significance of intra-specific variation in egg size as a determinant of offspring fitness within a life-history (sex-specific life-history strategies) and an environmental (poor rearing condi...

Chicken eggs represent an important source of protein to the growing human population and also supply repositories of unique genes that could be used worldwide. The inheritance of shank feathering trait is dominant upon non-feathering shank trait in chicken which is based on two factors: pti-1L and pti-1B that are located on Chromosomes 13, 15, and 24. Using 185 fertile eggs collected from two ...

This study aims to determine the effect of using Hermetia illucens maggot in feed on internal and external quality broiler eggs.The used 80 laying hens aged 6 months which were divided into 4 treatments, 5 replications each replication consisted tails. The variables observed eggs (egg weight, egg shape index, shell thickness, weight) white yolk Haugh units, color). data obtained analyzed with a...

The aim of this study was to investigate the differences in production performance, use of nest box, and external appearance of 2 strains of laying hens kept in conventional and enriched cages. Lohmann Brown Classic (LB, n=532) and Lohmann LSL Classic (LW, n=532) hens were housed from 16 to 73 wk in either conventional cages or enriched cages. Enriched cages had a nesting area, scratch pad, per...

The existence of a coevolutionary process between avian brood parasites and their hosts predicts lower intra-clutch variation in egg appearance host eggs among rejecters as this would favor discrimination parasite by once parasitic mimicry had evolved. So far empirical tests prediction have ignored the fact that different aspects phenotypes may differ relative role environmental vs. genetic det...

When successive stages in the life history of an animal directly overlap, physiological conflicts can arise resulting in carryover effects from one stage to another. The extreme egg-size dimorphism (ESD) of Eudyptes penguins, where the first-laid A-egg is approximately 18-57% smaller than the second-laid B-egg, has interested researchers for decades. Recent studies have linked variation in this...

In many organisms, large offspring have improved fitness over small offspring, and thus their size is under strong selection. However, due to a trade-off between offspring size and number, females producing larger offspring necessarily must produce fewer unless the total amount of reproductive effort is unlimited. Because differential gene expression among environments may affect genetic covari...

If the poultry industry hopes to continue to flourish, the identification of potential quantitative trait loci (QTL) for production-related traits must be pursued This remains true despite the sequencing of the chicken genome. In view of this need, a scan of the chicken genome using 72 microsatellite markers was carried out on a meat-type x egg-type resource population measured for production a...

A study was undertaken to evaluate the reproductive performance in two plumage colour variant strains of quail, viz; Brown, White Breasted and a dark Cinnamon Brown (commercial) strain. A total of 694 straight run active chicks were obtained in three hatches at weekly intervals from the three strains. Sex was determined at six weeks of age and female progenies were separated and data on reprodu...