The battle over gestation crates moved to a Des Moines Wal-Mart on Friday, where activists from Mercy for Animals protested outside a store at 5101 S.E. 14th St. The protesters put up a 10-foot-tall inflatable pig, bloody with sores and locked in a narrow crate. Mercy for Animals activists say an investigation showed that one of the retailer's main pork suppliers abused animals, and it wants Wal-Mart to require its pork suppliers to phase out gestation crates. Other retailers — including Costco, McDonald's, IHOP, Applebee's and Marriott International — have announced phase-outs of pork raised in such conditions. The National Pork Producers Council says gestation crates are safe and needed to prevent sows from biting each other's ears and tails. The crates are used by more than 80 percent of hog producers, according to industry statistics. Hog producers say an alternative system for Iowa's 1.9 million sows would potentially cost up to $500 million.