Captive chinchillas do best in pairs or small groups. They can be quite social with others of their own kind -- so they need room to play. You want to make sure the cage is sized so that the chinchillas you keep have plenty of space to play and live happily together.
Make It Tall and Large
Size matters when it comes to housing chinchillas. Most commercial cages are too small to allow room for the chinchillas to run and play. Chinchillas will jump between ledges, bounce off walls and run up ramps -- so when you make your own chinchilla cage, you want to be sure it's going to be big enough. The minimum size for one to two chinchillas is about 30 inches wide by 18 inches deep by 48 inches tall.
House Them in a Cabinet
If you want to build a cabinet-style cage, be cautious which materials you use. Your chinchillas will chew, and not all wood is safe. Avoid using oak, plywood, MDF, cedar and anything pressure-treated, as these products are not safe for chinchillas. Kiln-dried pine is a safe choice for building an enclosure, but you want to use melamine panels for the inside of the cage -- they won't absorb water and are easy to clean. The walls of the cage can be solid, but chinchillas need ventilation, so create a solid frame for the front doors and use wire for ventilation. Melamine can be heavy, so build the cage on wheels or casters so you can easily move the cage. If you make a cabinet-style cage, be prepared to have to replace ledges, shelves and accessories.
Or Within Wire Walls
A wire cage won't create the same effect as a cabinet-style cage, but they can be easier to make. You want to use wire that is thicker than chicken wire so it doesn't hurt your chinchillas' feet -- stick with wire that is larger than 16 gauge. The grid or wire spacing needs to be about a half-inch by a half-inch on the levels, ledges and the floor of the cage; the walls can have 1-inch by 1-inch grid. You'll need to use thick wire jump rings to connect the walls, crimping them tight to secure the walls. You want your chinchilla to have a solid surface on the bottom of the cage, so build up a gap in the front of the cage so you can slide in a tray to hold the bedding.
Fill the Cage
When you make a cage, you want to fill it with plenty of wood toys, wood houses, ledges, a dust box and other accessories. Avoid plastic, because your chinchillas will chew on it, and large chunks can come off and injure your pets. Wood will have to be replaced, but it's safe for your chinchillas to chew and play on.