In sheep country pigs are a massive problem. Sheep are not scared of pigs and pigs will/do eat the lamb even as they are coming out of the ewe's.

In Aust cattle and sheep farmers in Dingo country are between a rock and hard place. Dingo's will kill sheep adult and young and will kill young cows but they also help keep pig numbers down. So wild dogs are shot on sight and so are pigs.