I remember how the Scarecrow broke the necks of several crows in the book, and the Tin Man chopped the heads off of the flying monkeys with his axe. The slippers were also silver!
I loved how one of them, can’t remember which, nearly cried when stepping on a bug, then proceeded to kill a ton of other animals with no remorse.
It was self defense.
One of the biggest changes between the book and movie was that Dorothy had actually seduced a local politician, and Mrs. Gulch (the wife of said politician) arrived to confront Auntie Em over that, and not the dog. I was also surprised to read that Dorothy killed the witch by shooting her in the back with a revolver instead of pooring water on her.
I think MGM made the right decision to make the story more family friendly in those respects, although it is still pretty terrifying.