This time two ewes were mauled to death, another so badly injured it had to be euthanised, and a fourth is wounded.

The attack happened overnight on Saturday and this time the offenders have not been identified. The dogs responsible for the last attack were seized by council rangers and destroyed.

Teacher Anthony Carter said the sheep were fed on Saturday afternoon and discovered dead on Sunday morning.

"The unusual thing is that they were not in the paddock we left them in, they were two paddocks and three gates away from where we put them on Saturday afternoon."

The dogs movements were tracked, and it is believed they came onto the high school farm from the direction of the corner of Woodward and East Streets.

Mr Carter said one of the sheep was consumed.

"Quite a lot of meat was eaten - roughly around 7 kilograms - so we know more than one dog was involved."

Parkes High School Principal Sandra Carter has secured funding for a dog proof fence for the farm and until that is in place the remaining sheep will be moved to local farm.

"All we are thinking about at the moment is the security of the animals," Mr Carter said.

"It's about our animals now having a nice, happy life."

The attack comes as a warning to be vigilant with children and animals.

"The bottom line is I don't think I'd want one of my kids around when that is going on," Mr Carter said.

"An animal that can do that to a sheep can easily do it to something else."