It may not be the sport of kings, but they do bring home the bacon.

With the Spring Racing Carnival underway, followers of pig racing will not yet rival the crowds at Royal Randwick or Flemington racetracks.

But at agriculture shows such as Camden Haven at Kendall Village, south of Port Macquarie on the New South Wales mid-north coast, the pig racing enclosure is well attended.

Young children are rubbing shoulders with elderly people as they jostle for a spot at the perimeter fence as part of their day at the show.

Overseeing it is trainer, steward, race caller and judge Karl Mullon, who usually travels with seven piglets to the different venues.

"The reason we run pigs is that it is highly entertaining. It is very similar to thoroughbred racing — other than the size of the animals and the smell," Mr Mullon noted with a smile.

"We have a lot of fun with the kids and adults."

They are run in conjunction with local groups with the profits shared.

In this case it is the Kendall Public School.

A steel framed enclosure with a variety of obstacles such as ramps, barrels and hay bales is set up with a series of gates. A bowl of milk waiting for them at the finish line.

The gates are fixed by a latch which has also has milk spread on it.

When the pigs lick it, the pressure is sufficient for the latch to drop and the gate springs open for the next leg of the race.

"Pigs like milk like kids love ice cream. They will do pretty much anything to get a bowl of milk at the end," Mr Mullon explained.

Obstacles dot the track keeping the pigs on their toes with a different finish line for each event. ( ABC Rural: Michael Cavanagh )

Like thoroughbred racing, the distance run may change.

Unlike the sport of kings, the course itself varies each time.

"At the start the pigs don't know where the bowl of milk will be at the finish," Mr Mullon said.

"As the day goes on we raise the bar a little bit. The bowl at one finish may be on top of a hay bale. We build a moat sometimes with only one entrance.

"We have to keep the pigs interested. If they were going to the same place each time they would know exactly where to run. They would cut corners."

The pigs, which have a colourful jacket attached, hit the track from around four weeks old and after being weaned.

They continue racing till they are aged between 12 and 15 weeks old.

"One of the factors we use is that they look cute in the jacket. Then when they get a bit bigger they move on to another chapter of rural life," Mr Mullon said

He has been on the circuit for around four and a half years, "absolutely struck by just how intelligent these pigs are and fast these pigs learn".

While thoroughbred racing is governed very much by bloodlines, in the case of the pigs this is not a factor.

In between races the pigs spend their time grazing in the enclosure.

On this day, after rain overnight, the grassed area was soft and the piglets were turning the surface over with vigour.

"The pigs are first priority, the piglets we bring to these races. They are carted in approved stock rates," he said.

"When we arrive they are let out, fed, watered and they have shade. Sometimes they are pampered more than the humans that take them around."

Despite the enjoyment that Mr Mullon obviously gets from mounting the races, he has a pragmatic view regardless of how often they may greet the judge at the finish line.

"They are pigs and they are bred for fattening. We use them for a short period," he said.

"I haven't met one that I didn't like but I don't form an attachment."