Expansion of Iowa’s pork packer industry has slowed, hitting labor and construction snags.

The Seaboard Triumph Foods plant in Sioux City, expected to be running a double shift by the fall of 2018, has had challenges filling positions to run a full second shift, said Steve Meyer, an economist at Kerns and Associates, during a media call after the release of the U.S. Department of Agriculture’s (USDA) hogs and pigs report last week.

The new Prestage Foods of Iowa plant near Eagle...