"It's still early days, but the objective of the meat boxes is primarily to create a community of people who support what we are doing on the farm and take some responsibility in helping us regenerate the land," said Greg.
The couple made their farm operations more environmentally responsible and sustainable 15 years ago. All the meat at The Family Farm on the station is produced employing regenerative farming principles, such as a holistic grazing, that sequester carbon in the soil.
Unlike conventional farming practices where stock are allowed to graze pastures to low levels, the 500 cows, 100 pigs, 1000 breeding ewes and chickens at Mangarara are moved around constantly to maintain tall pasture.
Developed by Zimbabwean ecologist Allan Savory, the system has the animal "trample, poo and pee" on the taller grass which provides organic matter that breaks down to create richer, more fertile soils.
The taller pasture also has deeper, more complex root systems which in turn act as a natural filtration system for any farm water run-off, as well as protecting against evaporation and soil degradation.
Milk from the pasture-fed cows is used to feed the pigs and although they are fed some maize, the chickens are also mainly grass fed. Though the farm is not completely free of fertilisers, the couple use only the most biologically friendly ones and only when the compost from the station's two large worm farms isn't suitable.
"Basically we are growing pork and poultry that is fed on grass - because the milk is a derivative of grass - so it's requiring a whole lot less fossil fuel," Greg said.
"It's early days, but there are millions of hectares managed around the world this way. It's working for us and we think it's more sustainable."
The couple said as farmers, they were trying to be responsible stewards of the land, but they couldn't do it alone.
Rachel Hart said the meat boxes were a way for customers to show support for sustainability.
"The big thing that came out of the Havelock North gastro crisis was that people were quick to point their fingers at the agriculture sector [as the source the water contamination] but I'd ask those people if they know where their meat comes from. With our meat boxes, they do.
"And by supporting us they are allowing us to continue our tree planting and all the educational programmes we run out here," said Rachel, referring to the 105,000 native trees the couple have planted on the property - some with the assistance of the Air NZ Environment Trust - since 2008.
At the station's Eco-Lodge - overlooking Horseshoe Lake where they host about 100 schoolchildren at a yearly triathlon designed to help young people connect with the land - the couple also host international and national speakers on regenerative farming.
According to Paul Greaney, The Village Butcher in Havelock North, the couple's efforts are paying off. Mr Greaney does all the butchering for the meat boxes and described the quality of the beef, lamb and pork as "exceptional".
"It's export-quality meat you wouldn't normally get on the domestic market. The size of the muscle and the texture and colour is just exceptional. It's that good, I want to be able to sell it," he said.
Greg believed his boxes of premium, free-range meat were "incredibly good value".
"Particularly when you take into account the social and environmental benefits."
The meat boxes cost $180 plus postage for regular Meat Club customers or $200 as a one-off, and can be purchased from mangarara.co.nz, which also has free-range Christmas hams for sale.
