Police are appealing for witnesses and information after around 300 sheep and 120 cattle were stolen from a farm in Brant Broughton.
It is believed that at some point between approximately 8pm on Sunday, July 26 and 8am on Monday, July 27, offenders forced entry to a field near to Beckingham Range and stole the animals.
It is possible that the animals may have been offered for sale and investigating officers would like to hear from anyone who may have been approached by any individual selling sheep or cattle.
Also anyone who may have seen anything or anyone suspicious in the area around the time of the theft is asked to contact Lincolnshire Police on 101 quoting incident 235 of 27/07/2015.
Alternatively contact the independent charity Crimestoppers anonymously on 0800 555 111.