Genetic parameters for production, quality, and colors from eggs in Brazilian lineages of chickens.

Genetic parameters were estimated for egg production, egg quality, and eggshell colors in eight lineages of Brazilian laying hens. Age at first egg (AFE), total egg production up to the 45th week (PROD), egg weight (EW), albumen height (AH), yolk color (YC), the Haugh units (HU), eggshell strength (ESS), eggshell thickness (EST), yolk weight (YW), eggshell weight (ESW), and eggshell color (L*, a*, and b*) were measured in 2030 eggs obtained from 645 laying hens. Variance components were estimated from a mixed animal model, which included the fixed effects of contemporary groups, cage location, and hen line, and the additive genetic, permanent environmental, and residual as random effects.

Welfare indicators for laying Japanese quails caged at different densities.

In the way to reduce costs in the poultry production, high densities of birds are adopted in the production systems. Such high densities can lead to an inappropriate environment, compromising the welfare and decreasing the animal performance. In this work we aimed to evaluate the effects of different densities on the productive yield, egg quality and immunological aspects of Japanese quails.