Domesticated food producing animals in the world outnumber the human population, two to one. There are thousands of animal species in the world, yet, only a few have been successfully domesticated on a permanent basis and none within the last 2000 years. In fact, five species (cattle, sheep, goats, chickens, and pigs) comprise over 95% of the world’s farm animals and all five1 are found in the humid lowland tropics. Of all traditional smallscale animals in the tropics, however, chickens are by far the most common — as indeed they are worldwide.