Not first time dogs have attacked: council

A pair of dogs that mauled several farmyard pets at a popular NSW Blue Mountains cafe petting zoo have killed other animals before.

Two Staffordshire bull terriers dug their way into pens and caused carnage at Glenbrook's Cafe 2773, killing four chickens, a sheep, and maiming two pigs in the early hours of Wednesday.

The same dogs killed a goat and a chicken at another property in May, a Blue Mountains Council spokesman told AAP.

The owner of the dogs has been contacted and the animals have been secured, while the council determines what action to take.

Cafe 2773 manager, Dave Clarke, says the pigs have been badly mauled.

A neighbour, who was woken by the commotion raced out and was able to stop the dogs which were attacking the pigs.

"They (the pigs) have been badly mauled - they're recovering now, they're lying in the pen and they are not moving around much," he told ABC radio.

Mr Clarke said it's not the first time the animals at the family friendly cafe have been attacked by dogs.

The Blue Mountains Council spokeswoman said the dogs involved in the latest attack were not responsible for the earlier attack at the cafe.

The pigs are being treated by a vet for injuries to their snouts and legs.