The domestic chicken, Gallus domesticus probably originated from one of several jungle fowl, still found wild throughout Southeast Asia. 
Although the exact date of domestication is unclear, archaeological evidence places the chicken in human settlements in Indo-Pakistan by 3250 B.C. and in Egyptian tombs dating as early as 2000 B.C. 
The bird quickly dispersed throughout the world, both for its uses in agriculture and as a combatant in cockfights. 
Some scholars believe that interest in this "sport" was what led to the domestication of  the chicken. although it is of little importance to the commercial poultry industry, chicken breeds have been, to some extent, standardized. Many strains are crossed to achieve the ultimate type for layers or broilers and the exactbreeding is a closely guarded trade secret.