The longer I live and garden and eat as I do the more I understand why humans and various livestock animals have lived symbiotically for thousands of years all around the world. The animals get relative safety from wild predators that would otherwise kill them horrifically, often by eating them alive, plus are directed towards sources of food and water. In my case the ducks and chickens afford weed and bugs control, create fertile soil in the main path for me to use potting plants, provide me fresh eggs and now and then the meat that forty years of mindful adult experience as vegan, vegetarian and omnivore have taught me my body needs small amounts of a few times weekly for optimal health and vigor. Farmers I know who raise rabbits and goats and cows get milk, meat and hides and like me strive for the death of an animal at our hands be QUICK unlike a deer being slowly eaten to death by wolves. The fertility of my lot as a whole is increased, the birds get gourmet restaurant scraps, weeds I pull, the live bugs and lizards they relish, safe shelter at night plus shelter from rain, and drinking water enriched with iodine. It occurs to me that this symbiosis is a miniaturized version of the predator/prey and soil fertility cycles that have sustained life on the planet for easily three billion years. To me though, factory farming disrupts those basic cycles while subjecting many billions of animals annually to horrific, brief lives in nightmarish conditions while eating very poor quality food and being saturated with antibiotics and other drugs that are now breeding super germs. Sadly, with humanity breeding irresponsibly like bacteria in a sealed petri dish, factory farming may seem "necessary" to feed seven BILLION people wastefully at the cost of forests, aquifers and rivers, air quality and human health. I admire urban farmers and small local family farms who try to raise their livestock in comfort and with respect, just as native Americans did with the buffalo they utterly depended on, or the peoples of Tibet and Africa and the Middle East and Europe have done for many many centuries....true sustainability.