^ I'm in the same RI/what caused it? boat as you.
Picked up a nice big normal female last week, no symptoms when we got her from the previous owner then BAM when we got home (~1 and a half hour transit) she was rumbling and wheezing all over the place and after monitoring her mouth/throat for a week she had bubbles/mucus that didn't improve. Just got her in to the vet today and she's going to be on a round of antibiotics (Baytril).
I'm stumped as to why the symptoms seemingly popped up out of the blue in the matter of an hour but I'm thinking that the stress of the transit "triggered" it in a way and made it more apparent. That's just a thought though: I'm still confused!
Regardless of how yours got one (if it is indeed a RI) I would haul her to your vet just to be safe. As kitedemon said, it's better to catch it early than later.