Viorel Manu, 39, of Birmingham, was due to stand trial on Monday 23 March but changed his plea to guilty of conspiracy to steal in relation to the slaughter and illegal butchery of sheep and lambs.
He joins Robert Iordan, 23, and Florin Nutu, 36, both also of Birmingham, who pleaded guilty to the same offences at Northampton Crown Court on Friday 14 February.
Between June 22 and October 7 last year, Northamptonshire’s farmers had their livelihoods hit hard by the three men, who travelled across rural areas in the county, killing and butchering sheep in order to steal the meat and profit from it.
In total, 12 reports of illegal butchery were made to Northamptonshire Police during this period, with the Operation Stock investigation launched in response.
Lead investigator, DC Jamie Cooper, said: “These crimes caused farmers a great deal of upset and anger last year and I’d like to thank them and the wider rural community for their support and patience during our investigation.
“There was extensive media coverage when these incidents were taking place and I am very pleased we have achieved a successful outcome with all three men pleading guilty to their crimes.
“Operation Stock was a huge team effort and I hope this case shows just how hard we will work to protect the livelihoods of our farming and rural communities, who were deeply affected by this crime series.”
Detective inspector Johnny Campbell, added: “I would like to take this opportunity to say a big thank you to everyone who provided us with information throughout the Operation Stock investigation.
“Without a doubt, community intelligence was absolutely key in arresting all three of these men and being able to bring them to justice.
“Finally, I would like to thank DC Cooper, who worked tirelessly on this case to get justice for our rural communities.”
All three men will be sentenced by live link at Northampton Crown Court on Friday 27 March.