Police are appealing for witnesses after 58 young sheep were stolen from a field near Settle.
The Swaledale hoggs, which were born last year, were stolen between February 25 and March 25 from land at High Hill, Settle.
All of the hoggs would have had a green mark on their shoulders.
Farmer, Robert Cowperthwaite, of Stockdale Farm, said it was the second time in four years that he had lost sheep to thieves.
“I don’t really know yet what we’ll do, whether we’ll just struggle on as we are, or buy some more in,” he said. “It’s not right good.”
He said he had no idea how the sheep were taken, but believes who ever was responsible must have known what they were doing and had come with a trailer and possibly a dog.
A police spokesman said: “This theft is not only a huge financial blow to the farmer but it also impacts heavily on his future stock numbers and breeding programme for his flock.
“If anyone has any information about this theft of livestock or any other livestock theft then we would urge them to contact the police straight away.”
Anyone who can help should contact PC Barbara Parsons on 101 or e-mail Barbara.Parsons@northyorkshire.pnn.police.uk or Ingleton Police Sergeant Mark Hill on Mark.Hill@northyorkshire.pnn.police.uk.
Alternatively contact Crimestoppers anonymously on 0800 555111.