Well, the Lord does work in mysterious ways! Can you think of anything teen-aged girls like to ooooh and awwww over more than tiny little furry creatures? Sounds to me like the postman was the delivery man for the Good Lord "hatching" a plan to help you over the rough spots of the next couple of weeks. So be honest with her - tell her you are SO glad she's there because with the chickens you already have, the new ones coming, and now these quail, you really could use her help. Send her to the quail forums and turn those little dudes over to her. Let her know they have become "hers" and you trust her with them completely. Then you can use that as a stepping off point for how difficult it can be to parent....how decisions made are easy but living with the consequences is the tough part, loving and caring are full time jobs...you get the idea. And she'll just adore the little stinkers. Worth a shot, and seems like a win-win-win! You win because you can use the help, she wins because she'll be busy from day one, and the quail win because they have someone's undivided attention!
I know, I know....back in the corner, Blooie. <sigh>