"Could you turn the lights on?" I asked Terry, covered with goose bumps. "Just a little? So we can see better?"
"No. The lights have to be very controlled, so the chickens gain weight but don't get heart attacks. When the lights are on, the chickens are awake and eating and gaining weight. When it's dark, they stop eating. We don't want them to eat too much, because their genes are weird. They grow too fast, and their heart and legs get messed up. They get heart attacks. So, we need to control how much they eat, and we control it with the lighting levels."
Chickens and turkeys today are, in a sense, like balloons, except that they expand not with air but light. If they enlarge too fast, they explode - or, rather, implode, collapsing on painful, broken legs. Extreme genetic selection, accelerated by artificial insemination, has created farm animal breeds today that yield far more meat, milk, and eggs - while eating far less - than they ever have. The most astounding genetic changes have been those of chickens. In 1925, chickens reached a weight of two and a half pounds in sixteen weeks; today, they reach a weight of almost six pounds in six weeks. It's miraculous but torturous.