Carl Icahn, the billionaire investor known for his relentless campaigns against CEOs and rivals, has a secret cause that he has pursued for a decade.

In 2012, McDonald’s pledged to stop buying pork for its Bacon McDouble cheeseburgers, McRib sandwiches and the like by 2022 from producers who use small crates to constrain pregnant swine. Left unmentioned was that Icahn had pushed for the change behind the scenes.