Archaeology indicates that cattle were first domesticated in the Fertile Crescent about 8000 years ago. Evidence of domestic cattle was also found in Pakistan, from about 7000 years ago. Some archaeologists date domestication of cattle even earlier, about 9000 years ago, in Africa. From about 4000 BC oxen are harnessed and put to work. They dragged sledges and, somewhat later, plows and wheeled wagons.
Archaeological evidence indicates that chickens were also domesticated about 8000 years ago, in South and Southeast Asia. Interestingly, it appears that chickens were brought to the Americas even before the Spanish explorers arrival. Evidence of domestic chickens has been found in Chile from the year 1350.
Domestication of pigs and cattle is an indication of settled village life. Nomads got their meat by hunting and by herding sheep and goats, but villagers kept meat producing animals in the village. While hunting depends on luck and skill, domestic animals provide a constant source of meat (and milk, leather, wool etc.). Keeping live animals avoided the problem of leftover meat, which went bad after a few days. While the animals were still alive, they could be put to work and their manure could be used to grow crops.