[Vigilanteman]

The other question which should be asked is that do chickens actually evolve if they are intentionally bred with the best characteristics. Chicken breeding is a great hobby and/or profession because results can be produced in a relatively short time. They can go from just hatched to laying eggs in as little as five months, meaning you can get to the sixth generation in as little as three years.

[Secret Agent Man]

Breeding for characteristics causes the genetic background of successive animals to lose information. Higly purebred whatevers, are less genetically robust than prior generations.