Thanks everybody :) Giselle is feeling loads better today. She came out of her crate voluntarily and tried to do her little "Hey-you're-home!" dance. Before, I had to drag her out and make her poop/pee.
Also, don't worry. Ivy is staying. I have the final say, and this one incident isn't enough for her to get the boot =P Dr. Goodnow, I feel the same way. Prior to this, Giselle and Ivy were best friends, but thin grey skin and a large angry puppy just don't mix well. That said, we're taking careful precautions now and changing our routine. I just don't want to give Ivy a single smidgen of a chance to attack Gis or Lucky.