He's just turned 60, and reckons he can keep farming with such a reduced workload. "I love farming sheep and I set pretty high standards. I can continue doing that for quite a bit longer."
The McMillans farm sheep and beef at Ongarue, 25km north of Taumarunui.
They took two Ballance Farm Environment Awards - one for innovation and one for good use of water.
The innovation award was for their work with Wiltshire sheep, which shed their wool and don't need to be shorn.
When wool was worth just $2 a kilogram, Mr McMillan started thinking about all the things he had to do to harvest it.
Some of them got in the way of selling sheepmeat, which was getting better returns.
"Our whole operation was really around meat production, but we were making decisions around wool that was affecting our meat production. I thought wool was actually costing us."
He started an experiment, farming 1000 Coopworth and 1000 Wiltshire sheep, each under separate regimes.
For their Wiltshire flock he selected stock that shed as much wool as possible.
The ewe lambs kept in the flock are those with least wool on them in February, and every year he buys six to eight rams with as little wool as possible.
The Wiltshire breed very seldom has a problem with bearings or other birthing difficulties.
Because it has little wool sheep don't get cast or drown if they fall into water. He has 50per cent fewer ewe losses from his Wiltshires.
Wiltshire lambs are born with wool and very few die young, even in the cold of the central North Island.
The McMillan farm is sheltered and they have 140 to 150 per cent lambing, much the same for both breeds.
"There was one horrible long weather pattern that killed a few Wiltshire lambs, but they're not as vulnerable as people think."
In winter Wiltshires grow 25 to 60mm of rough, downy wool. The lambs put their energy into growing meat rather than wool, as do the lactating ewes.
"They're not trying to grow wool and lactate. Our observation is they stay in very good body condition with lactating."
Wiltshire ewe lambs are weaned in mid-January. Ram lambs are left with their mothers and sold in early February.
The farm needs secure fences to keep them contained as they get to maturity. They are sold without being castrated.
Wiltshire lambs are sold at 19kg-plus, and Coopworths at 16-17kgs.
The few new stock that come on to the farm can be quarantined. The Wiltshires have little chemical input and are less susceptible to intestinal parasites.
Mr McMillan hates the look of sheep with tails, but is now planning to leave the tails on all his Wiltshire sheep.
They don't need dagging, and any droppings that stick to them are shed with their wool.
The lack of dags mean they are much less likely to get flystrike.
"We had the odd flystrike, but it's never as severe a challenge as woolly sheep would get."
He's feeding the Wiltshires only on pasture, using set stocking, and has finished growing crops to finish the Coopworths.
"We've stopped any soil disturbance whatsoever. It's all grass finishing. I'm just taking advantage of the fact that there's no wool growth."
In two years the McMillans should have a pure Wiltshire flock and stop shearing altogether.
The experiment hasn't been perfect, but Mr Mcmillan has kept lots of data on it.
Naturally, a lot of other people are interested and he may be able to sell shedding ewe lambs in the future.
"These sheep aren't for everyone, or for everywhere, but it's an interesting concept the lack of time you need to spend and still get the same outcome."
