In 2008, Californians voted on Proposition 2, which requires California farmers to provide egg-laying hens, veal calves, and pregnant pigs with housing that gives them enough room to move around beginning January 1, 2015. The law would mostly impact the state's 18 million egg-laying hens. Current industry standards call for caged hens to get at least 67 square inches of space each, a little less than a regular-size sheet of paper (a sheet of paper is 93.5 square inches), and hens are typically caged in groups of two to eight. Proposition 2 grew into the most expensive animal welfare ballot measure ever, with both sides raising nearly $8 million each. The measure passed with 63.2 percent of the vote.