Horses became loose from paddocks in Newbiggin last week when vandals struck twice.
There were two incidents of damage at Store Farm Paddock in Collingwood Road.
And the damage caused allowed the animals to escape the holding.
It is believed the first incident was on Thursday night, Friday morning, and the second during Sunday morning.
Residents are being asked to be vigilant and report any suspicious activity to police.
A county council spokesperson said: “We are very disappointed at these incidents of vandalism.
“We have worked very hard to provide these paddocks for horse owners and were making great progress with addressing the horse tethering problems in the county.”