The Needham family, who own Higher Knoll Farm in Rivington, issued the stern warning to dog walkers last week after a rogue dog attacked a flock of sheep in lamb.
The farming family had been forced to destroy two sheep on Tuesday, February 19 after they suffered gruesome injuries in a dog attack.
It was the latest in a series of attacks on livestock at Higher Knoll Farm, where a total of ten sheep and a number of unborn lambs have been killed in recent weeks.
Megan Needham, 27, took to social media to vent her grief and frustration with dog walkers.
She has since launched a campaign - 'Take the lead in Rivington' - to remind dog walkers of the dangers of sheep worrying.
On Tuesday morning (March 6), just days after threatening to shoot dogs found on her land, Megan and her family made another grisly discovery.
Another two mutilated sheep, both in lamb, were found in a state of acute distress and the family were forced to make the difficult decision to destroy one of them.
It is hoped the other sheep might be able to recover after veterinary treatment. The attack caused both sheep to miscarry their lambs.
Megan said: "It's getting to the point where we are seriously considering selling our sheep. It's our livelihood and we just can't continue like this.
"Their faces were shredded again and the sheep were in a lot of pain and distress.
"We stand by our warning that dogs will be shot if they are caught off their leads on our land. It's the only way we can protect our livestock.
"Please, if you want to keep your dog safe and our sheep safe, keep your dogs on leads. It's really a no brainer.
"There is only one dog that will not chase sheep - the dog on a lead."