"The wrappers lasted between two to five days, depending on how exuberant the lambs were.
"They kept them warm and protected them for the first crucial 48 hours before they could start maintaining their own body temperature."
And with three strapping sons mowing through 14 loaves of bread a week, Owen was never short of material to make the "little wetsuits".
"We'd go through two loaves of bread a day, no sweat. I used to buy my boys brown bread, but their nana used to spoil them and bring over white bread," Owen laughs.
"They'd even have bread with their roast dinners. How gross is that?"
Pictured is a set of 1-day-old black lamb triplets rocking their raincoats in 1994.
"I would start saving bread bags six weeks before lambing to be stocked up," Owen explains.
"To me, it was a practical solution to a problem and it was very effective."
Nowadays, Owen no longer needs to construct the raincoats after going "upmarket" with a shearing shed to house the ewes and lambs when it rains.
"The sheep aren't a full-time occupation, they're my passion."
Owen says her family thinks her lamb-loving is eccentric, particularly her brother John Sefton, who took the photo.
Sefton, now illustrations editor at the NZ Herald, says his sister's sheep proved great subjects and were much easier to take snaps of than the ones roaming Cornwall Park.
"I called one of the lambs Toast after that shot, because it said 'sliced toast bread' on one of the packets," he quips.