Lamb rustling has soared by 250% in the past year, triggered by the increase in the price of meat.
Thieves are increasingly stealing lambs from farms and selling their meat on the black market for huge profits.
Officers from the Welsh Food Fraud Co-ordination Unit are investigating more cases of illegal meat sales than ever before.
The NFU Mutual had received claims for more than 60,000 stolen sheep by the end of October – two-and-a-half times more than last year.
Cattle, pig and game rustling have also gone up over the period.
“We’re concerned we could see further increases in crime as thieves see opportunities to steal livestock for the Christmas market,” said an NFU Mutual rural affairs spokesman.
“It’s a big concern that stock may be slaughtered, butchered and stored in unhygienic conditions, putting the livestock industry at risk and spreading disease.”
Anthony Sturge, who runs a catering business and farmer’s market stall from Brighton, said he had been approached three times by a man who offered to sell him a whole lamb for £55, well below the market rate, without a receipt.
“I personally haven’t taken any because I need full traceability for my products, but I can see that if someone knocked on your door and offered it, you’re not going to ask questions,” he said.
The figures are part of a report by The Grocer which reported that total losses in the industry had doubled to £5m as thieves were tempted by a price of nearly £4/kg for lamb.
The rise in livestock theft comes as meat prices soar across the board, with none more so than lamb, which has risen around 60% in the last three years.