Yikes!update - ok so I gave it a try and my girls tried to hurt her through the cage. I figured I had a rooster or she had something wrong with her. took her inside and picked her up and looked her over and she sneezed, so i listened to her chest and she was wheezy. took her to the vet and she had an upper respiratory infection. so she has been on antibiotics and vitamins and is cleared up but is still in quarantine till this sunday and I will try it again.
Did the vet send off any swabs for testing so you will know which respiratory disease you are dealing with?
Have you read up on respiratory diseases and have you considered there's a possibility that your existing birds can contract it as well?