Visitors put on overalls and boots before they enter, they are not allowed in if they have been in another piggery within 24 hours.
Hygiene is strict and the 30 animals added each year to provide genetic variety are quarantined first.
Indoors there are pens and pens of pigs, with weaned piglets all in together in age groups, and pregnant sows in groups of three to six. The pens are full of pink-skinned activity and the air occasionally rings with squeals.
The operation has about 10 boars. Fresh semen is delivered weekly from Auckland and 70 per cent of the sows are artificially inseminated.
There used to be a few smaller commercial pig farms in the district but they disappeared in the past 20 years, leaving only the Skiltons and lifestylers to keep pigs.
The brothers' parents, Allan and Doris Skilton, had pigs on their farm, but production stepped up 25 years ago.
These days there are two premises, one in Westmere and a new one in a remote corner of Maxwell.
Piglets and sows are housed at Westmere, with pigs moved to Maxwell for fattening at nine weeks old. There's a plant where their food is made, in a largely automated process, at each place.
The food consists of 75 per cent grain, 20 per cent imported soya and smaller quantities of products such as milk powder and fish meal, with the grain ground and everything mixed together. The Skiltons' cousin, Alan Taylor, grows about 60 per cent of their barley, and they buy from other local contractors and source some wheat from Canterbury.
The pigs eat through 1500 tonnes of barley and 700 tonnes of wheat annually.
Pigs are tropical animals, the brothers say. They are housed in eight buildings, a total of 4000 square metres. The buildings are insulated and temperature controlled, 18C to 20C for adult pigs and 30C for piglets in their first six weeks. There are 120 heat lamps going day and night for the babies.
"They're like little humans without any clothes on," Ross Skilton said.
Keeping pigs in close proximity to each other makes them vulnerable to disease. The Skiltons like to limit the amount of medication in their feed, hence the stringent hygiene measures.
Sows that are newly pregnant are liable to abort if stressed. The Skiltons keep them in single crates for the first month after mating, something animal rights people have said is cruel. But they say pigs are territorial and isolation protects them from attacks by other sows.
The effluent the animals generate every week is screened and used to irrigate about 200ha of pasture, which is grazed by a mix of 70 per cent dairy and 30 per cent beef cattle. About 25ha a year, in rotation, goes into crops.
The Skiltons are about to add another treatment process for their waste, before it is spray irrigated. They have built a sealed, anaerobic treatment pond at Westmere. It has the additional benefit of producing methane gas, which they plan to burn to heat their piggery buildings.
There are only a few other farms trialling this method in New Zealand and it should reduce odour.
After fattening the pigs are sent away for slaughter, about a third of them to Land Meat in Wanganui, one of just four facilities for killing pigs in the North Island. The rest are killed by Auckland processors, with the main buyer the Progressive Enterprises supermarket chain.
Aorere Farms is a member of Five Star Pork, which co-ordinates supply across about 10 farms. Some of their pork becomes Kiwi Bacon, processed in Hamilton and now owned by Goodman Fielder.
The brothers say pork prices in the first half of last year were down, while the price of grain was up; a bad combination. Since then pork prices have stabilised and the business is economically sustainable. But they're now worried about the potential introduction of a deadly disease and competition with overseas producers, if Government decides to allow the import of fresh pork.
Pig farming has gone the way of other farming, with farms getting bigger to decrease costs through economies of scale. There are about 100 commercial producers of pork in New Zealand, but thousands of hobby and lifestyle farms with a few pigs each.
AORERE FARMS
370ha farmed, at Westmere and Maxwell
Also 120ha of bush on one property
4500 pigs, indoors in eight houses
1000 cattle
50 tonnes of food a week
Effluent spray irrigated on to 200ha of pasture
240 pigs killed each week
One-third of those at Land Meat
Rest processed in Auckland
