John Gregory, who is a seventh son of a seventh son and also the local spook, has protected the country from witches, boggarts, ghouls and all manner of things that go bump in the night. However John is not young anymore, and has been seeking an apprentice to carry on his trade. Most have failed to survive. The last hope is a young farmer's son named Thomas Ward. Will he survive the training to become the spook that so many others couldn't?
Thankfully both dogs I can recall from the film (the first being at Tom's home right before he is recruited by Gregory, the second at the town right before it is attacked by the witches) are not seen being harmed in any way & don't have much presence in the film.
A couple of the witches in animal form die (the giant bear, the leopard...) though they are clearly not real. There were no deaths of 'real' animals throughout the movie