Bend chicken wire into the basic form of the rock that you want to create. You will need to cut pleats into it with wire cutters to create curves and angles. Twist the extending wires together to make the form hold its shape. Leave the bottom open.
Cover the chicken wire with bird wire, which has smaller holes and will better hold the cement.
Mix a batch of cement according to the instructions on the package. It should have the consistency of thick peanut butter.
Spread the cement over the wire rock form. It should be at least an inch thick.
Buff the cement with a wet rag once it has partially hardened to smooth the surface and remove any rough areas. The amount that you smooth the cement depends on what you want the finished rock to look like.
Let the cement fully harden for two days.
Color the cement with concrete stain if desired. Brush the stain on unevenly, then wipe off the excess with a rag.