The Alliance meat co-operative is undertaking research to see whether shorn lambs grow faster than woolly ones.
The idea is to inject some facts into a rural legend - one believed by many farmers - that shearing lambs destined for slaughter helps them bulk up.
Alliance Group technology officer Hayden Peter says field trials have begun on five farms across the country, at each of which 400 lambs will be divided into four groups, each with the same live weight.
Mr Peter says one group will be shorn, one will be belly-crutched, one will be brought in but not shorn and the other will remain woolly in the paddock.
He says the lambs will be weighed at the start and monitored throughout the trial and every three weeks until they are slaughtered in six weeks' time. Results should be available by the middle of the year.