Mr Mawson, who has farmed the property since 1990, said his neighbour lost six sheep to rustlers in 2012 and believed stock theft in Hawke's Bay was a growing problem.
"They must have had a hell of a quiet vehicle because where they took the ewes from is only about 15m to 20m from the house and my bedroom," he said.
"It's getting easier for them. They are quite cunning, and they don't seem to worry about getting caught."
He valued each ewe at $140 to $150 on today's market and said it was "quite a hit", while his grandchildren, aged 2 and 7, were devastated to lose their pet.
"We just called her Lamby. One of the little ones was really upset about it and couldn't get to sleep the next night."
Mr Mawson had contacted police about the theft, the second such reported incident after fellow Hawke's Bay farmer Lester Colvin, profiled in Hawke's Bay Today Weekend on Saturday, also lost stock to rustlers.
Mr Colvin set a combined $1000 bounty for information leading to the arrests of the thieves, in the hope of identifying them before they continued to send sheep to "backyard" slaughter.
Taradale and rural community police officer Senior Sergeant Peter Gimblett told Hawke's Bay Today last week that rustling had become a regular occurrence in the region and there had been a noticeable surge.
He said thieves were targeting four or five animals at a time and could be using a car and trailer, a utility or even a large hatchback car.
