I read this collection in 1980 or 1981 (unsure how old it was at the time). I checked it out of a public library in the armpit town of Stead, Nevada.
Anyway, in the story, some asshole's dogs chase down a boy who's cradling his two small puppies. I think the boy climbs a tree but the puppies fall from his jacket and are mauled by the dogs. Later, the boy somehow becomes a werewolf and sneaks out at night to kill the two dogs. But then the boy forgets why he became a werewolf in the first place and now he's just a werewolf.
There was even an ILLUSTRATION, a creepy one, the head of wolf on the body of a full clothed boy. Like a dressed wolf walking around on two legs.
Would love to figure out what book/story this is from.