Cut the pine planks to fit inside the cage. Cut two planks approximately 1 inch shorter than the width of the cage. Cut two more planks to be 3 inches long and two more that are 5 inches long.
Sand the wood planks on all sides to prevent injury to you while working and to make all smooth and comfortable for your pet.
Stand a 3-inch plank up on its side so the cut edge faces up. Repeat this with the other 3-inch plank, then place one of the longer planks on top to form a shelf shape. The 3-inch planks should line up just under the short ends of the longer plank.
Position an L-shaped bracket on the underside of the shelf where the top meets one end. Use a drill and a screw bit to attach the bracket to the wood. Repeat this with another bracket on this end of the shelf, then attach two more to the opposite end.
Repeat the process of steps two and three to create a taller shelf with the other long piece and the two remaining 5-inch planks.
Place the shelves inside the cage for your chinchilla to climb and rest.