Hi, this is the task for the companion addon "Crack It" for Object Cell Fracture addon
This addon requires the Object Cell Fracture addon to be active before using & suitably informs the user of this requirement in the ui.
Once executed the addon calls the object fracture & adds it's own displacement settings, resulting in rock like formations & more.
Thread with links to docs: https://blenderartists.org/forum/showthread.php?404683-Addon-Crack-It-Make-Crack-for-Tree-Poop-Rock-etc
Current file with "Excrement" material changed to "Organic_Mud" & materials file compact.