Perthshire farmers are being warned to be on their guard after £13,000 of sheep were stolen from a farm near Falkirk.
Rustlers made off with 96 of the animals from the Denny site, which has not been identified, some time between January 30 and February 18.
The farmer discovered the crime while carrying out a vaccination programme on his 800-strong herd.
He discovered that 46 mule sheep, worth £150 each, missing, alongside 50 Texel crosses worth £120 a head.
The National Farmers’ Union Scotland said such incidents can be devastating to livestock keepers.
The organisation’s livestock policy manager, John Armour, said: “Rural crime remains a blight on our countryside and livestock rustling and animal theft is a growing problem.
“NFU Scotland and our members are working closer than ever with Police Scotland to prevent theft and recover stolen livestock.
“While the amount of animals’ subject to theft is very low overall, livestock rustling can be devastating to those farmers who are victims of criminal activity.
“The fate of these animals is unknown but I urge farmers and public alike to be alert to people looking to sell livestock or meat where the origin of the goods cannot be guaranteed.
“We also call on anyone who lives and works in the countryside to keep their eyes peeled. Almost every theft requires some form of transport and if you spot an unusual vehicle or suspicious activity, please take the time to call 101 and report it to Police Scotland.”
A spokeswoman for Police Scotland said: “We received a report of sheep stolen from a farm near Denny.
“The farmer counted on January 30, when all 800 were accounted for. He started a vaccination process on February 14 and thought there was some missing.
“On February 18 he completed the vaccination process and having scanned all the sheep he realised that 96 were missing – 46 mules, worth £150 each, and 50 Texel crosses, worth £120 each.
“All of the sheep were double tagged and there was no obvious breaks in his fences.”
Last year more than 100 sheep were taken in a large scale raid on farm land near Comrie.
The animals were taken from the side of the B827 Comrie to Braco road over the course of the summer.
Around 115 ewes were taken in the raid, though given the timeframe it is unclear whether they were stolen all at once.
Police valued the animals at £11,500 and said they believed organised national and international gangs are targeting Perth and Kinross and Angus farms.