Hymn Lyrics Search - Name That Hymn

my mother in law and her sister are tryin to find the title and artist of a song about a boy who has a bird with a broken wing in a cage. and he tells a man that he is going to kill it and the man offers to buy it because he wants to set it free just as jesus paid for our sins....this is all they can remember about the song other than them saying it was sad. any help would be greatly appreciated.