There are no national regulations in the United States, but several states, under pressure from activists, have adopted bans on the use of sow crates in hog production. These typically have been smaller states that have pretty small populations of hogs, but the Humane Society of the United States has an aggressive campaign to secure petitions that are going to increase the number of these bans state by state. There are several cases of states that will commit to eliminating sow crates by 2017 or beyond and—
On May 14th, 2012. See this statement in context.