My Dad's a sheep farmer – he'd never take a shot at a dog worrying his sheep. He's such a rubbish shot, one blast with a 12 bore would do more damage to his flock than a dog would! I remember going into Mole Valley Farmers and him asking for cartridges that make the biggest 'bang', just so he could scare, in this instance, Rooks that were flattening the wheat crop.
I did stop a pair of dogs attacking some sheep in the summer. Stopped at the next farm and told the farmer. Apparently the dogs belonged to the neighbour and had attacked previously. The farmer had warned the neighbour, followed by a caution from the police for the 2nd event. Sounded like my 3rd report was going to be the end of the dogs.