Has it actually taken up residence or is it using your barn as a stop-over till it finds a better place? Either way, you need to get it into a hive before it leaves or starts making comb. If it is excessible, I would get a super with wax in it and smoke the bees, then carefully brush them into it. If they have started making comb you are going to have a more difficult time getting them into the super but you won't have to worry about them taking off.

jbdollar,
could you possibly be J. Dollar who live part of the year in Poinsettia Park. Florida

Diane
Hope you don't mind this note of enquiry.