Wow, sounds like her situation was not fun!
It is possible that she was chewed by a cagemate, or that she chewed herself. Stressed chins will do that. If after a while the fur does not grow back, then it is most likely her chewing, or something else.
When you take her to the vet, have them check with a UV light for ringworm, too. If it was a hot building, it's possible it was humid as well --- breeding ground for ringworm and other fungi.
Until you're sure of what has caused the hair loss, you should really quarantine her from your current male. Ringworm can travel as spores through the air, and on skin and clothing.
You do not want to risk your male catching ringworm, or anything else for that matter, from this new girl.
I suggest a minimum 4 week quarantine, and a vet visit as soon as possible.
Congrats on the new addition!