David Ottley runs a small outdoor pig herd at Ottley's Blue Welly Farm in Bacton, supplying free-range pork and hog roasts.

But he was devastated to find four of his animals dead after two apparent attacks last Friday and Saturday night.

Two were trapped in stock fencing after having been "spooked" enough to run into an electric fence, and two others in a separate paddock appeared to have suffered heart attacks, he said.

He believes it was a deliberate attempt to scare or steal the pigs - having ruled out an attack by a wild animal due to a lack of bite marks or tracks.

To add to the mystery, he spotted a black Transit-type van driving away down a farm track on Sunday night, and when he mentioned the pig deaths at a slaughterhouse on Monday he discovered another farm near Fakenham had recently reported a similar experience.

Although police have been informed, Mr Ottley admits there is very little evidence to go on - but he is warning other farms to be on their guard.

"I have been doing this for 30 years, so I know when something is just not normal," he said.

"We have lost four pigs. Two were stuck in stock fencing, which is highly unusual. These pigs have been behind electric fencing all their lives, so they know what the fencing is. For this to happen, something has really spooked them.

"They chose to go through the electric fence and hit the stock fence behind it so hard they were knocking fence posts down.

"The other two in the other finishing paddock had definitely had heart attacks. They must have been terrified, because you don't normally end up with dead pigs like that either. It is really strange.

"I initially thought it might be animal rights activists or someone playing silly buggers. It could have been someone trying to steal the pigs.

"We have nothing to go on, there is no evidence. But I am certain it is human activity. If it was an animal there would have been marks on them.

"There has certainly been some strange activity and we have just got to raise awareness that people should heighten their security.

"It could literally mean checking your animals later in the night, and watching who is around during the day."

© Eastern Daily Press