Globally, there are about 5.5 million (55 lakh) layer parents (parents of pullets) and 500 million (50 lakh) broiler parents (broiler breeders). Greater progress in efficient production has been accomplished by the application of genetics to poultry than with other livestock.
Key features of the market are reduced time to market (to less than half), an increased market weight (to more than double), and a reduction in feed required (to less than half).
These changes predominantly reflect tremendous genetic improvement through selection. There have also been great improvements in egg production.
Breeding of poultry differs from the breeding of other livestock animals. First, the breeding program is based on pedigree and/or grandparent or great-grandparent lines. These are subjected to intensive selection. Second, there is a much larger number of generations that have been subjected to the intensive selection due to very rapid reproduction. Third, breeding/genetics is predominantly concentrated in a few large international companies.
For today’s poultry production, closed pedigree lines are subject to intense selection. From these, great grandparent and grandparent lines are derived. These lines may be crossed to give parent lines that are in turn crossed to produce the broiler chicks, pullet chicks, or turkey poults. The broiler chicken industry takes advantage of hybrid vigor, or heterosis, to increase growth rate.
In developing high-performing genetic stocks, breeders have applied quantitative population genetics together with inbreeding, hybridization, genomics, and other techniques. Commercial breeding requires excellent beginning stock (germplasm), scrupulous recordkeeping, and the application of population genetics, statistics, and computing to evaluate genetic stocks and progress from selection. Commercial breeding of poultry has three objectives: (1) Increased product output per bird (or unit space); (2) increased efficiency of production per unit feed; and (3) improved quality of the product (e.g., increased breast muscle yield in broiler chickens) and disease resistance.
For broiler chickens, turkeys, and ducks, the major indices are improvements in growth rate and feed conversion. For layer chickens, the major indices are egg production and feed conversion. In addition, improvements in the following are desirable: fertility, hatchability, body conformation, meat (particularly breast) yield and quality, egg size and quality, and livability.
Tremendous progress has been made in improving the genetics of broiler chickens and turkeys.
The impact of genetics has resulted in the following:
Data from Havenstein et al., 2003a; b; 2007.
- 4.6-fold increase in growth rate in chickens as indicated by body weight at 42 days old.
- 2.2-fold increase in growth rate in turkeys as indicated by body weight at 112 days old.
- 51-point improvement in feed conversion in broiler chickens.
- 30-point improvement in feed conversion in turkeys.
- 74% improvement in breast weight as a percentage of body weight in broiler chickens.
- 23% improvement in hatchability.
It should be noted that improvements in poultry nutrition, incubation, and health have also made strong contributions to the success of poultry production.
Origin of Commercial Egg Layers
- Origin of white-egg layers—White Leghorns
- Origin of brown-egg layers—the dual-purpose American breeds, Rhode Island Red and White Plymouth Rock
Origin of Broiler Chickens
- Male—Cornish (compact bodies with high proportion of breast muscle)
- Females—dual-purpose American breeds such as Barred Plymouth Rock, White Plymouth Rock, and New Hampshire
