Seth, At what point in time did you decide to give your chin Benadryl? While taking out some of the factors which caused Phoebe issues, I am finding that the fall allergy season is here and she is sneezing more. I know it is not a URI as she has no wheezing or drainage. Thank you.
Welcome to your new pets.
I second not breeding the two and keeping them totally separate all the time if they are male and female. (Double check their genitalia to make sure they are male and female.) Do spend some time reading the forum and learning a little bit more about your new friends...
URIs can be spread to chins the same as humans, through simple exposure. You may have the virus but be asymptomatic. Washing your hands before and after contact with your chins can be very helpful. Also, don't have contact with them if you are sick.