Whats less processor intensive?

Adding / removing children (could be 10 times every few seconds)
These children also have several animations associated with them

or

Adding all children once, and simply placing them out of stage view, and calling them back when needed to the stage (these will be still be running through their animation sequence while offstage, or they can be stopped)
child.x -= 10000;

My guess is the latter?

Thanks!