The Sierra Club works to educate the public about the impact of the factory farms on our health, the environment, local economy and animal welfare and to offer local, sustainable alternatives to the industrial food supply. Unfortunately, most of our meat, dairy, poultry and eggs are produced in very unsustainable animal factories, and our runaway consumption of animal products is a significant factor in the issue of climate change.
Today, the majority of meat, dairy, poultry and eggs we eat is a product of CAFOs (Concentrated Animal Feeding Operations). These industrial operations are defined by the Environmental Protection Agency as having more than 1,000 beef cattle, 2,500 hogs or 100,000 broiler hens. Industrial agriculture is based on the financial bottom line, not on the welfare of the planet, consumers or farm animals affected by these operations. Living a Nightmare: Animal Factories in Michigan
produced by Future Media Corporation of Okemos, Michigan.
Lynn Henning, Sierra Club Water Sentinel, farmer, Goldman Prize winner
Gail Hansen, DVM, MPH, Sr Officer, Pew Charitable Trusts
Joe Maxwell, Vice President, Outreach and Engagement, HSUS, farmer, former Atty General of MO
For the whole story, check out this powerful book:

