Well, Broadway shows are required to hold auditions every 6 months, Wicked or not. But since it is required, that doesn't always mean they are looking for somebody. They go through the motions to just do it because they have to. Sometimes, they are though. I don't know if they hold auditions in between them, though.
"This table, he is over one hundred years old. If I could, I would take an old gramophone needle and run it along the surface of the wood. To hear the music of the voices. All that was said." - Doug Wright, I Am My Own Wife