Welcome to the forum!
You really should quarantine -- but since she is a friend, do you handle or get close up with her chickens? Have they ever had anything like sneezing, cough, runny eyes or nose? (If yes to any of these, I would not take her.) How about lice/mites, or scaly leg mites? If you handle them then handle your own, or handle things in the coop, or walk on poop from both places, yours have very likely already been exposed to anything they might have. In this case, you might choose to trust that they are OK, to ease things for your daughter.
For the introduction, some distraction might help, like giving both some treat. If you happen to have a place you can introduce them that is new to your own, maybe a garden, this will help. You could put a little food and water in separate containers so they can each have their own, at least til you see how it is going to go. Places to hide can help. One method is to slip the new bird on the roost at night, just after dark. Sometimes they seem to think the new bird already belongs there by morning.
Maybe you will get lucky, and it will just be some mild pecking and sizing up.
