Introducing a 3rd conure

We currently have a bonded pair of Male green cheek conures (we're assuming they're male. They havent laid eggs in the 2 years we've had them). Our friend is looking to rehome a female green cheek.

We're wondering if theres a safe way of introducing them and caging all three of them together. Or do we need to keep her separate??

You need to keep them separated. Often what happens is a bonded pair (even two males can bond strongly) will see the new bird as an intruder to their territory, and if housed with her, will likely injure and kill her.

Have you thought of DNA'ing them? It's super cheap and easy, online they offer tests for around $12. Then you'll know for sure.

There's no guarantee any new bird will be liked by old bird, ESPECIALLY if the two you have are a bonded pair. They will likely show a lot of aggression and want her to stay away. When birds bond and pair, they develop very strong protective instincts with each other and will make it known they are not happy with outsiders.

It's never wise to get a bird for existing birds you have, especially seeing as yours are so close they will likely reject her.

Just warning you that it could go very badly. Under no circumstance should you put them all 3 in the same cage.

Kept separated, with time out of the cage away from the other birds, she may be a nice pet, but I wouldn't expect her to be accepted by the bonded pair you have.

I wouldn't do it. You may be disturbing the balance between the two you already have. Conures are very territorial and this trio may not go so well.

Be married and have a stranger move into your bedroom with you. Possible issues?