The chickens used by KFC are battery hens. These are chickens that grow in outrageously bad conditions (just very cruel overcrowded conditions) – they are fed antibiotics because under the conditions they live they basically get sick if they are not fed antibiotics. They are kept under lights to force them to eat all day and quickly reach a weight that is economical. There is a fine maths that happens to get chickens to grow as quickly as possible in as little space as possible. So rule one – if you want to eat a “happy”, humanely raised, antibiotic free chickens, you need to go free range.