I've heard too that the quick gets worn down by walking. It's been raining the past week and she won't even step foot on the ground if it's wet!
Well, I was thinking if I was to have them cauterized, now would be the time since she's going to be under for her spay. I could see how it might hurt her for a few days, but I don't know if it's the same for dogs in that way... Hmm. She will be on pain medicine, but I'll ask their opinion about the being too short = painful.