Cowspiracy: The Sustainability Secret is a 2014 documentary film produced and directed by Kip Andersen and Keegan Kuhn. The film explores the impact of animal agriculture on the environment, and investigates the policies of environmental organizations on this issue. Environmental organizations investigated in the film include Greenpeace, Sierra Club, Surfrider Foundation, and Rainforest Action Network.
Here is the link to the official website of the film.
And here you may watch the trailer of the documentary film.