A bantam is a small variety of poultry, especially chickens. Etymologically, the name bantam is derived from the city of Bantam, once a major seaport, in Indonesia. European sailors restocking on live fowl for sea journeys found the small native breeds of chicken in Southeast Asia to be useful, and any such small poultry came to be known as a bantam. (from Wikipedia)
Being smaller they are suitable for today's world as they do not need so much space whilst they can still lay well, though the eggs are smaller than the larger birds. The Bantam eats the same type of food as a normal bird but less of it.