You will probably end up with dead birds. What you did was wrong, if you wanted to get a bird then you should have bought one from a pet store or bird breeder.
I've pretty much have wanted a bird since forever and when I realized there where some in my chimney I went crazy. Yes it's the most cruel and mean thing. Ever! And I think I'm the only one who has ever done that D; and I can here the mom coming sometimes and I really want to give her babies back! But there's no nest and the chimney is so complicated. 1st I feel horrible I cried cause I'm a bad person and 2nd what can I do