I'm with Bobert on terriers, not just regarding size:

Knew a fella owned a purported champion stud Airdale, planned to make his fortune hiring it out. Lived in a rural, woodsy area.

I came across him at the village cafe one afternoon, he was ranting like a lunatic. Dog was with him, face all scabby. "I'm gitten a gun and shootin every damn porcupine on the gawwdam mountain! This is the FIFTH time I had to bring Big Expensive Canine to the vet to get quills out!!! *Rant, rave, threaten porky genocide*"

"Five times?" sez Bee.

"Yes, he's just healin' up and runs across another one. *Rant, spit, snarl*"

"You got a dog here that didn't figure out after the first four facefuls of quills not to stick his nose in a porcupine's hind end? Buddy me lad, my advice is, leave the porcupines alone and shoot the dog: it's too stupid to live."

He didn't agree, but I noticed he gave the dog away shortly after. I hope they had it neutered.