More than half of New Zealand's pig farmers could be left in financial ruin if a first-of-its-kind court challenge is successful.
The High Court is reviewing whether the use of cages in pig farming is actually illegal under the Animal Welfare Act.
It's the first case of its kind in New Zealand and "the most significant animal welfare decision and case in a generation", according to Marcelo Rodriguez Ferrere, a senior law lecturer at the University of Otago.
About 60 percent of pigs farmed in New Zealand are raised indoors. Most of them are inseminated in cages, and forced to give birth and raise their piglets in cages - known as farrowing.
Mother pigs, or sows, can only take a few steps forward and back in the cages. They cannot turn around, and cannot perform instinctive behaviours, like nest building.
"It's severe behavioural restriction, and physical restriction, for the breeding sow," said the SPCA's senior science officer, Rob Gregory.
Animal welfare groups have been trying to get farrowing crates banned for years. They were the subject of one of the largest ever parliamentary petitions, by SAFE, with 112,000 signatures.
But the pork industry says farrowing crates are essential because they protect piglets by making it less likely for them to be crushed by their mother.
One or two piglets on average are saved per litter on indoor caged farms, compared to outdoor farms.
Farrowing crates are so contentious, there is disagreement about what to call them. They are technically cages, but the Government calls them crates, and the pork industry calls them pens, saying it's a "dramatisation" to call them cages.
Now the fight to have them banned has gone to the High Court in Wellington.
SAFE and the Animal Law Association, represented by Queen's Counsel Gillian Coumbe, have asked the court for a judicial review of the Government's decision to allow cages to be used in pig farming.
The respondents are the Attorney-General, the Ministry for Primary Industries, and the National Animal Welfare Advisory Committee (NAWAC).
The case hinges on the relationship between the Pig Code of Welfare, created by NAWAC, and the Animal Welfare Act.
There are codes of welfare for every farmed animal in the country, and they outline the specific rules for each animal, in line with what is allowed under the Act.
The Animal Law Association is arguing that the permittance of cages in the code is actually illegal under the Act, because of the behavioural restrictions forced onto sows.
"The argument is that there isn't enough scientific basis or justification for allowing farrowing crates, that alternatives are possible, that NAWAC should have looked at those, and the failure to do so meant that they exceeded their powers under the Animal Welfare Act," Rodriguez Ferrere said.
The good and the bad of farrowing crates
Farrowing crates are allowed by the Government and defended by the pork industry because less piglets die when sows are put in cages - sows unwittingly roll on top of their piglets, crushing them, in all types of pig farming.
Around 12 percent of piglets die in caged farming, versus about 17 percent in outdoor farming.
In a 2016 review of farrowing crates, NAWAC said "confining of sows in farrowing crates… does not provide for every behavioural need of sows, [but] their use provides the best welfare outcome for the welfare needs of piglets and the best total welfare of piglets and sows".
Indoor farming with cages is also environmentally better compared to intensive pig farming outdoors, and safer for staff.
"Nothing else has been determined to be better than this system, to look after and balance the needs between the sow and the piglet," said Southern Pork owner Jason Palmer.
But one study from Massey University found 89 percent of piglets die within the first week of life, and NAWAC's best practice, which is not widely followed, is for sows to only spend 15 days in farrowing crates.
So the pork industry was told, in NAWAC's 2016 review, to work "towards a shorter time in crates, [and] replacement of crates" - but it's yet to do so.
"We don't believe there is a better alternative," NZ Pork chief executive David Baines said.
Alternatives include farrowing pens, where sows have room to turn around, and freedom farming, where piglets are born outdoors and then moved into open-sided barns after weaning.
But more piglets die in both, and every dead piglet represents hundreds of dollars lost.
Retrofitting farms would be costly if cages are banned.
"If change was to come it would be devastating for our industry. It would wipe out more than probably half of the indoor systems in New Zealand," Palmer said.
There are only about 100 pork farmers in New Zealand, meaning about 30 farms could be forced to close.
An economic analysis of farrowing systems, commissioned by NAWAC in 2015, concluded "enforcing a move to a one-week farrowing pen system using new buildings was financially unviable".
"Such a move would most likely face considerable resistance from producers and if implemented may result in a large decline in the New Zealand pork production base, with the gap in the market taken up by imported pork and other meats," the report said.
The free-range alternative
Only about 1 percent of pork farmed in New Zealand is free-range. There are only two commercial free-range pork farms.
They are much smaller than indoor farms: One of them, Longbush Pork in the Wairarapa, has just 55 sows on 20 hectares, compared with 60 sows in one shed at Southern Pork.
The pigs are farmed entirely outdoors, from birth to death.
Owner Naya Brangenburg, a former vet and animal welfare inspector, says she's mitigated piglet crushing without cages.
"We have smaller litter sizes with larger piglets, more robust piglets. We also have very maternal mothers. So a combination of those two factors contributes to less [crushing] problems," she said.
Brengenburg doesn't believe cages are necessary: "We're just not willing to compromise and have sows in crates. It's just not something that we believe is how they should be treated," she said.
"We're already asking pigs to give us their lives. We're asking a huge amount. How can we possibly ask them to compromise more of their natural behaviours, the natural, positive things that happen in their lives?"
"These animals are more intelligent than your pet dog. We wouldn't do that to our companion animals. We wouldn't do that to a dog."