Oh poor Regina and poor you Jackie! My guess is that she got bitten by something, it could have even been a bug in the house. Don't worry too much as long as her breathing is fine. I've had many cases of hives over the years with boxers and Bulldogs, usually due to bug bites. Once, though, I took my son's boxer to doggy day care to be evaluated in preparation for leaving him there for a weekend. He got along with the other dogs (no fighting), but he stayed off to himself all the time (2 hours). When I brought him home, he broke out into hives. I can't be sure that stress caused it, but I'm pretty sure that was it. People can get hives from stress, so I guess dogs can. Also, hives look pretty scary on short haired dogs. I now have a dog with long hair and I'm wondering how I would ever know if he got hives! Anyway, Regina will probably be good as new in a few days!