Henderson Fire Chief Brandon Phillips says the fire was reported about 4:30 a.m. Sunday by a passing motorist.
The Star Tribune reports the barn housed about 400 hogs, but crews were able to cut holes in the walls to let about 150 hogs escape.
Phillips said the rescued hogs were moved to another barn in Renville. He told the Star Tribune there were two other hog barns nearby and crews were fortunate to not lose another one.
Crews were at the scene about four hours. Fire departments from Le Sueur, Arlington and Belle Plaine assisted.
The fire is under investigation, but Phillips says an electrical wiring problem might have been the cause.