My daughter killed a small rabbit when she was 4 year old. I was not there but the story is that mom tried to take it away from her and she got overly violent trying to snatch it back out of mom's hands. Clearly she did not have the bunny's welfare in mind in this moment or she would have been more gentle. I don't see a difference between her actions/motivations and that of an overly rambunctious puppy. In general, my daughter is a very kind, compassionate, caring person.