Broken planks? Maybe u could knife it up a bit and simply just move the points around... You could also entirely break off some pieces and just re-insert them away from where they were before at an angle where it might look more "jaggedy".
But then again, depending on how far its gonna be, and since you also said only a silhouette, I don't think either that too much detail or even much texturing is required on this part...
