Or if there is, they are not saying.
The Murrays, of Brookvale Farm, Waitahuna, said their lambs did not get any special treatment.
"They come straight off the hills and don't get a chance to get fat," Mr Murray said.
The couple were surprised with their win as they "didn't cut the mustard" in the local competitions.
Finalists in last year's competitions, the Murrays won first place in the dual purpose section, taking the title of grand champions, as well as winning their own section.
The finals, or Glammies as they are also known, took place at the Upper Clutha A and P Show, in Wanaka earlier this month.
The Murrays run about 2450 Romney-Perfintex breeding ewes (half Perendale, quarter Finn and quarter Texel), and 30 breeding cows on their 389ha property in the hills above Waitahuna.
The couple arrived on the farm in 1973 and initially ran Perendales, before changing to Romneys, then Border Leicesters.
Buying Perfintex rams from Alan Williamson, of Poolburn, has improved their lambing percentage and carcass yield, Mr Murray said.
Perfintex were great all-rounder sheep - hardy, like the Perendale, good milk-producers, like the Finn, and high-yielding, like the Texel.
Their lambs were now yielding up around 60% or 70%.
He said that 12 out of the 16 finalists in the Glammies had Texels in their mix.
"The Texel breed is really coming through ... They are a good, meaty carcass."
They tried to keep the animals' lives as stress-free as possible by not "stirring them up", he said.
"They're weighed off a fortnight beforehand, dagged, and sent into pasture on a good sunny paddock with good feed."
The key to good meat lay in good farming practices, Mr Murray said.
"We're just casual cockies really. We just like to feed them well and drench them when required. They don't get special treatment."