The decomposing body of a truck driver and married dad who disappeared before Thanksgiving was found in an Iowa field last week — and police have no clue as to how he ended up there dead.

David Schultz, 53, of Wall Lake, Iowa, went missing Nov. 21 after heading out with his rig to pick up a load of hogs for a livestock peddler.

Schultz collected the pigs but disappeared on his way to deliver them, with authorities later finding his rig about 10 miles from his destination — with no sign of him and the hogs still packed into the trailer.

A massive search with more than 250 volunteers scoured about 100,000 acres looking for the missing man but never found a single trace of him, so the hunt was called off.

Then last week, police got a call about a body in a field not far from where the truck was found.

Dental records — and the man’s boots — matched Schultz’s, officials said. His keys also were found in the body’s pants pocket.

But what happened to him remains a mystery — although police said they don’t suspect any foul play, based on an autopsy.

Jake Rowley, a team leader with the nonprofit search-and-rescue team United Cajun Navy, which helped in the search for Schultz last year, said it is not clear if his body “was there the entire time.”

The dead man’s grieving widow told reporters, “He was such a good father.

“It’s not fair.”

With Post wires