Carolyn Press-McKenzie signs her name on one of 1500 pieces of paper in support of stricter regulations to help intensively farmed animals following a fire which killed 50 pigs in Hopuhopu.

OPINION: There is, as the saying goes, no smoke without fire. So when 50 sows and their piglets died from incineration and smoke inhalation last Friday, eyebrows began to rise.

An investigation by the Ministry of Primary Industries has now been opened to find out just what caused this latest fire at the Hopuhopu piggery in question.

This piggery has previously been in the news for three fires over the last 10 years, claiming the lives of more than 700 pigs. As jokes about smoked bacon started circulating on social media, others felt a stunned grief.

On Sunday, animal rights activists held a vigil outside the piggery and 1500 signed plaques taped to a fence to pay silent honour to the pig's lives.

Fifteen hundred voices were raised to say that enough is enough. This cannot be allowed to happen again.

The cause of the fire is thought to be electrical. John Darroch, a Farmwatch investigator who has twice visited the facility, is quoted as saying that it was "dilapidated" and rats were observed running over wiring. It had neither sprinklers nor a fire extinguisher. The spotlight may be on this particular farm, but the fact is that piggeries all over New Zealand are places of unbearable suffering for pigs.

The fire that swept through this farmer's property on Friday destroyed mothers and babies crammed into dark, concrete crates that are standard in 67 per cent of New Zealand piggeries. The mother pig can only stand up and lie down. She has legs, but she cannot use them to walk.

There is no straw for bedding. She scrapes her nose over the bare concrete floor in a vain attempt to build a nest for her young. The soft "singing" she would comfort her young with in nature is replaced by deafening screams as she rails against her every thwarted instinct, and her inability to escape her torture. She has her piglets for four weeks, before they are taken away to be fattened for slaughter.

She is reimpregnated and the cruel cycle begins all over again. This will continue until she is spent and sent to slaughter at a fraction of her natural lifespan.

This is the reality of factory farming of pigs in New Zealand. Pigs are intelligent animals who have out-performed three-year-old human children on cognition tests, and who are considered by some animal experts to be smarter than dogs.

The Ministry for Primary Industries and the NZ Pork Board must also take responsibility for this recent tragedy. It is not known if the Hopuhopu farm was NZ Pork "Pig Care" accredited, but the Canterbury pig farm where shocking undercover footage was made public in 2014 was. That footage showed dead pigs, pigs with bleeding wounds and seeping sores, pigs with rats running over them, pigs going silently mad as they gnawed the bars of their pens in despair.

MPI staff, responsible for the welfare of farm animals in this country, must have smoke in their eyes. They are clearly unable to see the animal cruelty right in front of them. Piggeries are not up to scratch in this country, and changes need to be made as a matter of priority.

It is time to set up an independent voice for animals who can conduct inquiries into the welfare of farm animals with the ethical standard required.

* Sandra Kyle is an Otorohanga teacher and writer. Lynley Tulloch is a lecturer in sustainability education at Waikato University. Both are animal activists and Free FM broadcasters.