Sheep had their throats cut by thieves who removed their innards at the scene and then stole the carcasses in a sheep rustling incident in Kirklees.
Incidents released under the Freedom of Information Act revealed 14 thefts in Kirklees and Calderdale since 2012 and a total of 36 county-wide.
In October 2013 thieves raided an unnamed Kirklees farm and stole nine sheep after killing them at the scene.
A Force report: “Location is a farm in a rural area containing sheep...unknown persons approach gate, enter field and by unknown means capture nine sheep.
“Suspects then cut the throats of the sheep and remove the innards, discarding these at the scene. The sheep carcasses are then loaded into the suspects vehicle and suspects make off unseen and unheard.”
The culprits have not been caught.
One of the largest thefts was in December last year when 83 sheep were taken from fields in Leeds. In February this year 20 pregnant ewes were stolen from a Bradford farm and in March 26 Scottish Blackface sheep were taken from moorland in Bradford.
A Force spokesman said: “We would encourage anyone who has been a victim of this crime to come forward to the police with any information to assist with our enquiries.”