Warning: The following story contains references to animal cruelty.
The Ministry for Primary Industries (MPI) is investigating two live pig selling businesses and has warned a third after all three advised customers they can use a household hammer to knock the animals out before killing them.
Phone recordings show all three companies suggested the method - despite it clearly being in breach of the law.
A video markets pigs delivered live to your door.
"Plenty of puaka. Want some? Come and get it," the video says.
But suggesting animals can be stunned with a hammer has horrified the animal rights group SAFE.
"It's very cavalier and it's abhorrent and I think most people would be pretty surprised and shocked," SAFE investigations and rapid response manager Will Appelbe says.
The companies - Island Time Pigs, Mr Pig and Funga Puaka - operate live pig delivery services on Facebook.
All three were recorded by a volunteer from SAFE posing as a customer.
A representative from Island Time Pigs offered advice after the caller said he didn't have a gun.
"Just a hammer to the forehead and then stab it in the throat," the Island Time Pigs NZ representative said.
Then a staff member of Mr Pig offered similar advice.
"I would just stun it with a hammer and then stab it in the heart," the Mr Pig representative said.
As did Funga Puaka.
"Just donk it on the head with a hammer or something strong," the Funga Puaka representative said.
Appelbe says that this is potentially happening in people's backyards by novices is "seriously concerning".
"It is concerning to us that this sort of advice is being given to people who are buying live pigs. It doesn't reflect best practice," adds NZ Pork animal welfare scientist and advisor Dr Kirsty Chidgey.
The code of welfare for pigs is clear and applies to anyone who buys a live pig. Only unweaned piglets can be stunned using a heavy object like a hammer. But such a method of stunning is prohibited for larger animals. A captive bolt or firearm "must be used" to stun pigs before they're bled out.
And while unweaned piglets can be stunned using a heavy object it's only allowed in an emergency, for example if they're injured.
But the companies' pages market large animals weighing between 20 and 30 kilograms for $220.
Island Time Pigs uses farmland in Taupiri where it transports live pigs to the public around Waikato and Auckland.
Newshub spoke to the owner.
"There are recordings of your staff suggesting it's okay to stun a 20-25 kg pig with a hammer, '' Newshub’s Investigations Reporter Michael Morrah asked.
"Well, that's what normal people do," the Island Time Pigs owner responded.
"Yeah, but that's against the law," Morrah replied.
"Yeah, we understand that," the owner said.
He said he's raised the matter with staff.
"It's something that we learn from and just keep moving forward."
The operator of Mr Pig told Newshub MPI has spoken to him.
"Just basically abide by the rules and regulations so it's all good," he said on the phone to Morrah.
He then hung up.
No one from the third company responded to requests for comment.
"Very surprising that these businesses are either ignorant of the Code of Welfare or willfully ignorant of the Code of Welfare," Appelbe says.
MPI told Newshub it "provided advice and education" on humane slaughter to one operator. The other two businesses are still being investigated.
The body that represents commercial pig farmers didn't know about the live delivery Facebook businesses.
"They've never been audited because they're not registered with NZ Pork. We just have no visibility of these sorts of operators, unfortunately," Dr Chidgey says.
And that's why animal welfare advocates say a proper inquiry into the prevalence of such operators and the potentially cruel advice being offered is warranted.