A growing trend

• McDonald's and Wendy's, the No. 1 and 2 burger chains, asked their pork suppliers this year to outline plans for the elimination of gestation crates but didn't set a timetable.

• Chipotle, with more than 1,200 restaurants, uses free-range, hormone- and antibiotic-free pork, as well as "naturally raised" chicken and beef.

• Smithfield Farms and Hormel committed to ending the use of the gestation crates by 2017.

• Wal-Mart and Costco have shifted their private-label eggs to 100 percent cage-free.