How to select poultry line?/ how to select poultry genetic for the breeder stock?

Concepts and Methods of Poultry Genetic Selection

Single Line: Breeder uses a closed flock, continuously selecting the better birds each generation and breeding from them. Hybrid Vigor: Outbreeding which results in increased quality of the hybrid offspring.

Male Line and Female Line: Crossing of a Male line only line with a Female online line. The opposite sex of each line is destroyed at day 1 of age.

Strain Cross: Crossing of two or more different strains rather than selecting for traits within one strain. Only a few desired traits are selected within each strain rather than all the desired traits in one strain.

Two-line Cross: Allows for offspring to have positive traits from both lines, however, at a lower rate than the original lines.

Three-line Cross: First a two-line cross is done then the offspring of that cross are crossed with a third line to obtain more positive traits.

Four-line Cross: Two separate two line crosses are completed than the offspring of these two crosses are bred to obtain offspring with traits from all four lines.

Strains used for crossing must nick: This means that the two lines that are being crossed must complement each other.

Inbred Crosses: Crossing of related individuals to improve uniformity. This often reduces performance. Performance can be restored by crossing lines.

Sex-linked Meat Lines: Certain feather colors and speed of feather growth can be linked to the sex of the bird. The trait will only appear in one of the sexes, making separation of chicks at hatch easier.

Layer breeding programmes In commercial layer breeding programmes, selection addresses the following areas: • Egg production and size: Genetic improvement in egg production and size is challenged by the highly canalized nature of the trait as determined by diurnal photoperiodic constraints; negative genetic correlations between egg production and early egg size; variation in the rate of increase in egg size with age; and the need to predict persistence of lay in birds selected for breeding before the third phase of production. High-capacity computers and sophisticated statistical packages involving Best Linear Unbiased Prediction (BLUP) procedures have been used to predict persistence in the laying performance of birds in current flocks, allowing selection to take place earlier and the maintenance of a relatively short generation interval. • Egg quality: Shell quality is defined in terms of strength, colour, shape and texture; the first three have moderate to high heritabilities, so respond readily to selection. Shell colour is determined almost exclusively by genotype, and selection is typically based on measurement using reflectance spectophotometry. There are cultural preferences for eggs of different colours. Shell strength is a critical factor affecting profitability. Breeders have selected for improved shell strength by measuring shell thickness, specific gravity (of fresh eggs), shell deformation, and other indirect and direct parameters. Shell texture and shape aberrations and blood and meat spot inclusions are selected against by culling birds producing these eggs. Albumen quality has been improved by selecting for increased albumen height measured using a Haugh unit micrometer. • Selection in barn and free-range environments: Effective selection for egg numbers and quality was not feasible in the past, when birds were housed under group pen conditions in barns, or free-range. Recently, technologies have been developed for attaching transponders to the birds and the nest box, with sensors that allow egg production to be recorded and eggs to be traced back to the hen that produced them, for quality measurement. 

For more detail: http://www.fao.org/3/a-al726e.pdf