Dog owners are being urged to keep control of their pets after three ewes, carrying seven lambs, were attacked and killed in Chapel-en-le-Frith.
The ewes, due to lamb in two weeks time, had been grazing in fields adjacent to Sheffield Road and were all fine when checked on Friday afternoon.
But on Saturday morning a check revealed three of the flock had been attacked. One had been savaged about the throat, with the other two, who were less injured, found lying dead nearby.
The ewes had been scanned previously and were due to produce seven lambs between them.
It is feared the horrific deaths resulted from an irresponsible dog owner allowing dogs to roam free.
Now the National Farmers Union (NFU) has urged dog owners to take responsibility for their pets, which should always be kept on a lead near any sort of livestock which includes sheep, cattle and horses.
Alison Pratt, spokeswoman for the NFU in Derbyshire, said: “This happens all too often.
“It is so unnecessary. The public really must take heed of where their dog is and keep it on a lead at all times if livestock are near.”
She said many dog owners had no idea about the damage that their pets can inflict and issued the plea as farmers prepare for the lambing season.
“At home they may be the sweetest, kindest dog but it can only take one incident to turn it into a sheep worrier.”
She explained that dogs do not have to physically attack livestock to harm them. Sometimes just getting too close and worrying them can frighten a ewe and lead to her aborting her lamb.
Farmers can shoot a dog if it is worrying their livestock but must have just cause before taking such action.
Dog owners who allow their dog to worry livestock can face a £1000 court fine
A Derbyshire Police spokeswoman said: “If anyone is found to be responsible for letting their dogs worry sheep action will be taken against them.”