Turns out Marcy is actually "Yodi" and is a Presa Canario, not a pitbull. Shockingly, she does have an owner - a guy who trains guard dogs. Somehow the dogs got out. I don't quite understand it myself - that's why I plan to find out why these dogs were so underfed, smelled more than they should, and seemingly had not been to a vet in a very long time. Case is not closed, but I wanted to update you, since we no longer have her here.