Every chicken in New Zealand is eating GM soy

It's the cheapest meat in the supermarket. It's in school lunches, on weeknight dinner plates, in Sunday roasts, in the fried chicken bucket, in the supermarket sandwich. New Zealanders eat around 40 kilos of chicken per person every year — roughly 20 whole birds each. That's chicken on the plate two or three times a week for most households. For some, every day.

So it's worth knowing what your chicken is made of.

Here's the honest answer: a New Zealand meat chicken lives for about 35 days, and for most of that life soybean meal makes up somewhere between 15% and 25% of its diet by weight. The exact ratios are commercial secrets, but soy is the protein backbone either way. It's how the bird grows so fast, so cheaply.

New Zealand grows almost no soy. We import nearly all of it. The bulk comes from Argentina, with smaller volumes from Brazil and the US — all major GM-soy producers.

That matters, because the soy from these countries is not just any soy.

The soy is genetically modified. All of it, more or less.

Roughly 100% of Argentina's soy crop — and around 95% of Brazil's and the US's — is genetically modified. It was engineered in the 1990s by Monsanto to survive being sprayed directly with glyphosate, the active ingredient in Roundup. The seed and the chemical are sold as a package. You buy the seed, you buy the spray, you spray your fields, and only the soy survives.

The way they made the soy is worth pausing on. Monsanto found a strain of bacteria that could survive glyphosate — it had evolved that resistance in the waste tank of one of their own glyphosate factories, swimming in the chemical effluent. They took the resistance gene from that bacterium and inserted it into soybeans using a gene gun. Literally a gun, firing DNA-coated particles at soy cells. The cells that took up the gene were grown into plants, sprayed with glyphosate, and the survivors became the seed line.

That's the soy your chicken is eating.

And it's been sprayed. A lot.

Argentina sprays around 300 million litres of glyphosate every year, across more than 28 million hectares of farmland — around 60% of the country's arable land is now soy. It runs one of the most glyphosate-intensive agricultural systems in the world. Farmers spray four to seven times a season, at roughly twice the rate the chemical was originally trialled at, because weeds keep evolving resistance and the only answer the system has is more.

300 million litres a year. Argentina runs one of the most glyphosate-intensive farming systems on earth. Most of it goes on soy. Most of that soy gets fed to chickens, pigs, and dairy cows somewhere else in the world.

The chemical doesn't wash off. Independent testing of Roundup Ready soy has found residues averaging up to 9 milligrams of glyphosate per kilo of harvested beans. USDA testing has found lower levels — closer to 1 mg/kg — but conventional and organic soy grown in the same regions tested clean, because those plants would have died from the spray.

That's the soy that travels across the Pacific in cargo ships, gets crushed into meal in feed mills, and ends up in the trough. It's also part of the much larger story of how dependent New Zealand has become on imported food — but that's another piece.

The chickens spend their entire lives on it

Thirty-five days. Day after day after day, eating glyphosate-residue soy as a significant share of their diet. By the time the bird is slaughtered, it has known no other food. Whatever the soy is made of, the bird is largely made of.

When researchers actually look at what this does to the birds — and a major review in the World's Poultry Science Journal in 2025 did exactly that — the picture is not reassuring. Glyphosate disrupts the chicken's gut bacteria. It shows up in liver and kidney tissue. It affects egg yolk composition. In laboratory studies, embryos directly exposed to glyphosate show developmental abnormalities. The doses in those studies are higher than ordinary dietary exposure, but the mechanism — disruption of cell signalling during development — is established.

The chicken's own body is showing signs that the chemical it eats every day is doing something to it.

Inghams found out about this in 2009

Here's a piece of New Zealand history most people have forgotten.

In 2008 and 2009, Inghams — one of New Zealand's biggest chicken producers — ran an advertising campaign claiming their chicken contained "no GM ingredients." The Commerce Commission investigated. It turned out Inghams' chickens were eating feed that was 13% genetically modified soy. The Commission warned them. The campaign was pulled.

The Commission engaged Professor Jack Heinemann from the University of Canterbury to look at whether GM material could actually transfer from the feed into the meat. His conclusion: he was "in no reasonable uncertainty that GM plant material can transfer to animals exposed to GM feed in their diets or environment, and that there can be a residual difference in animals or animal-products as a result of exposure to GM feed."

That was seventeen years ago. The system hasn't fundamentally changed since. The soy is still imported, still mostly GM, still sprayed with glyphosate. Nobody is putting "fed on GM soy" on the label, because by current rules they don't have to. The international regulatory position is that GM feed doesn't change the meat. Whether that conclusion has been tested as thoroughly as the question deserves is a different matter.

What does this mean for the human eating it?

This is where honesty matters, because the answer is not as clean as either side of the argument wants it to be.

Most of the glyphosate in human bodies — and it's measurable in 60–80% of the general population, including children — comes from cereals and bread, not meat. Direct residue testing of chicken meat tends to come back below detection limits. The industry line is that the chemical doesn't accumulate, and that the meat is clean.

But the World Health Organization's cancer agency, the International Agency for Research on Cancer, classified glyphosate as a probable human carcinogen in 2015. That classification has not been withdrawn.

Bayer paid out $11 billion. And then it got stranger.

Here's the part that's hard to argue with.

Bayer, the company that bought Monsanto in 2018, has paid out around US$11 billion to settle Roundup cancer lawsuits — roughly 100,000 cases. In February 2026 they proposed another $7.25 billion class settlement to resolve future claims. The cases are mostly from people who developed non-Hodgkin lymphoma after long-term Roundup exposure.

Bayer maintains, through all of this, that glyphosate does not cause cancer.

It's worth sitting with that for a moment. A company with the world's best lawyers and an army of scientists has paid out eleven billion dollars while continuing to insist the product is safe. That isn't the move of a company that thinks there's nothing wrong. That's the move of a company that's calculated the cost of fighting versus the cost of paying, and chosen to pay.

But it gets stranger.

While Bayer's agriculture division has been paying out billions to people with non-Hodgkin lymphoma, Bayer's pharmaceutical division has been selling a non-Hodgkin lymphoma drug. It's called Aliqopa (copanlisib). The FDA gave it accelerated approval in 2017 for relapsed follicular lymphoma — a subtype of non-Hodgkin lymphoma. They withdrew it in late 2023 after a confirmatory trial failed to show enough benefit, but for six years one Bayer division was selling the chemical that critics say causes the disease, and another Bayer division was selling the drug to treat it.

You don't have to believe in conspiracy to find that arrangement uncomfortable. You just have to be able to read a balance sheet.

The system question

Even if your chicken breast tonight contains no measurable glyphosate — and it probably doesn't, at the limits of current testing — the system you're feeding from looks like this:

A chemical the WHO calls a probable carcinogen, sprayed in volumes that have made one country's farming system among the most chemically intensive on earth, on plants engineered specifically to absorb it without dying, fed for 35 days as a significant share of a chicken's diet, two or three times a week onto your dinner plate, every week, for most of your life. Sold to you by companies that won't put "GM-fed" on the label. Owned by a corporation that has paid out eleven billion dollars while insisting the chemical is safe, and that until recently was selling the cancer drug for the disease people were suing it over.

Maybe that's all fine. Maybe the dilution is so great by the time it reaches you that it doesn't matter.

Or maybe a system that pays out eleven billion dollars while insisting nothing is wrong is telling you something it doesn't want to say out loud.

A way out

You can step outside this system. It costs more on the receipt — there's no point pretending otherwise — but the framing matters.

Certified organic chicken in New Zealand is fed on certified organic feed, which by definition cannot contain genetically modified soy or maize, and cannot have been sprayed with glyphosate.

The main nationwide producer is Bostock Brothers, a Hawke's Bay family operation that raises chickens on the family's organic apple orchards and grows their own certified organic feed. A whole Bostock organic chicken at the supermarket is around $18.50 a kilo. A standard supermarket whole chicken is around $6.84 a kilo.

It's tempting to look at that and say organic chicken costs nearly three times as much. But it's worth turning the question around.

What if $18.50 a kilo is what chicken actually costs?

What if the real number is the price of feeding a bird food that wasn't sprayed with a probable carcinogen, raising it slow enough to develop properly, and giving it room to move? What if cheap chicken is cheap because somebody else is paying the difference — the soil in Argentina, the rural villages near the spray fields, the chicken itself, the gut bacteria of the children eating it, the health system thirty years from now?

We're not paying twice as much for organic. We're paying half as much for the conventional version, because the real costs have been pushed somewhere we don't see them. They show up on someone else's bill, in someone else's body, in someone else's country, in someone else's future.

The same logic applies to certified organic eggs — the hens are eating feed that hasn't been near glyphosate, and the price reflects what it actually costs to feed them properly.

If certified organic is out of reach, the next steps down — pasture-raised, free-range with transparent feed sourcing, small producers willing to tell you what's in the feed — at least let you ask the question and get an answer. Most supermarket chicken doesn't even let you do that.

The point isn't that every household has to switch tomorrow. It's that most of us have never been told the chain exists. We've never been given the chance to even know what we're choosing between.

That's the real cost of cheap chicken. Not what's on the price tag. What you don't see.

More from OFT on chicken and eggs: organicfoodtogether.nz/tag/chicken/