Chinchillas are very active animals and therefore need a good size area to live in. This is a necessity for a happy and healthy chinchilla. Even if you only live with a single chin, the minimum size cage you should consider purchasing is 36"h x 18"d x 30"w.
Basically, there are two styles of cages you see most often and can choose from. A drop-in pan and a wire bottom with slide-out tray. The drop-in pan has no wire flooring. The cage fits into a galvanized or plastic tray bottom that you add litter to. Some people prefer this type of cage because they don't want their chin to be standing on a wire floor. These types of cages may also need to be cleaned more often if you have more than one chin because the chin is directly on the wet litter. A wire bottom cage has a tray that pulls out from under the wire flooring. There is nothing wrong with a cage that has wire flooring, as long as you provide several solid surfaces for your chin to rest on if he would like to. When pulling out the tray for cleaning, do so carefully if your chin is on the bottom floor and watch out for his toes in case the tray is a snug fit. Any wire flooring /shelves or ramps should be 1/2" x 1/2" mesh for your chin's comfort.
The ideal size of wire mesh for the outside body of the cage should be 1/2" x 1". You can find some cages with 1" x 1" wire spacing as the outside body of the cage and this is also acceptable. The two most popular brands of cages that have this size wire spacing is Martin's Cages and Quality Cage.
I recommend Martin's Cages as a good and safe chinchilla cage. Many of the cages in our rescue are made by Martin's cages. The smallest cage you should consider is their Chinchilla Skyscraper model R-695, but of course you can get a larger cage if your budget allows and you have the room for it. You can get a drop-in pan or pull-out tray, whichever you prefer. When I order a Martin's Cage, I tell them to leave out the middle floor and no ramps. So basically I just use the outside body of the cage and the two half wire shelves that come with the cage. I use both drop-in pan and pull-out tray type of cages. Then I add all the extra goodies. The cage has two doors in the front. You need to assemble most of this cage and having two people makes it an easier job. They send you c-rings and disposable pliers which can leave the c-rings too loose, so make sure you tighten them with a pair of needle nose pliers. You don't want any parts of the cage to have gaps or any of the levels to rattle when your chin is jumping on them.
When many people assemble these cages, they accidently put them together backwards. So keep in mind when you are looking at the front of the cage, the highest 1/2 wire shelf should be on the left side. You then have the middle floor in which the opening (with the ramp leading to it from below) will be toward the back of the cage. The other 1/2 wire shelf will be lowest on the right side. I highly recommend you completely remove the ramp that is on the bottom floor level since a chin does not need it and it only takes up room and is one more thing to have to clean around. Also, the front panel of the cage should have the lower door on the left front side with the door hooks going over the wire (not under). If you do purchase a running wheel for your chin when you get the cage, the wheel will not fit through the doors so install the wheel before attaching the front panel of the cage. If you purchase a wheel at a later date, you can always partly remove the front panel and squeeze the wheel through at that time.
Here are two photos of Martin's Cages. One is with the middle floor and ramps as you would receive from Martin's and the other is with no middle level, but wooden shelves which I installed.
The Quality Cage also has nice cages and they are very popular among chinchilla parents. They have the 1" x 1" outside bar spacing and it is basically a drop-in galvanized pan, but they have designed it with a pull out tray. This cage has one large door. The cage comes with wooden shelves, but not enough of them in my opinion. They leave too much space between jumping surfaces and you should definitely plan on purchasing extra shelves from them or make your own. You should also add wooden ledges as steps.
Another very popular cage is the Critter Nation cage. This cage is basically a bird cage that has been around for many years, but now it has been slightly altered with cut-out trays if you want to use it as a two tier cage. It has 1/2" horizontal bar spacing which is the maximum spacing you should have. This cage also has a protective coating so keep in mind that a chin can chew off any coating on a cage if he is inclined to. Some people do not use a middle tray and fix the cage up as a large open space, while others use the plastic tray as a divider for a first and second level. One of the issues to consider with this cage is that the tray is only about 1" high which will be more of a mess if you have a chin that likes to pee in the corner of the cage. Keeping any bedding in the tray with it being so shallow poses a problem. Most people who use these types of cages use fleece liners in the trays. You would need to sew your own or find someone who sells them. They need to be changed often since your chin would be peeing on the fabric. Some people have said their cage is not as fresh smelling despite washing the fleece liners while other people swear by using fleece liners. Because the trays are not deep, using wood shavings will be messy. All of the ramps in these cages have horizontal bar spacing. I do not recommend these types of ramps ever unless you keep them covered at all times. Having only horizontal bars is not safe for your chin and we have rescued many chins with amputated legs because their cages contained these. So basically, I would recommend two options. One is to remove all the shelves and ramps from these brands of cages and replace them with wooden ledges and shelves or second you can cover the half plastic trays and wire ramps with fleece fabric. The Ferret Nation cage is also very popular among chin parents now. I myself have recently added several of these cages to our rescue. The bar spacing is about 7/8" and I wish it was smaller, but many people love these cages. They too can be used as one large cage or divided into two cages with an upper and lower level.
I highly advise you to get galvanized replacement trays for the Critter Nation and Ferret Nation cages. These are a deeper tray which will keep all the bedding inside the cage and since chins often will chew the plastic trays that normally come with these cages, the metal trays will prevent this. You can get metal trays that fit both the upper and lower levels at Bass Equipment Co. You also have the option of ordering two solid one piece trays rather than one solid tray and one with the corner cutout. If you need to divide the cage into two, you can just use two solid trays to block the corner opening.
What about making a homemade cage? Some people would like to make their own cages. If you want to try this, safety needs to be your first priority. The cage needs to be very sturdy since your chin will be romping around in it. You can get wire that is 1/2" x 1" or 1" x 1" at most home improvement stores. You want galvanized after weld. You will need to have some kind of a tray to put the cage in and there are some cage suppliers that allow you to purchase just a tray. If you use wood as framing, your chin will chew the parts he can get to. It should also be a safe wood for your chin in case he does chew it. Do not paint or stain it for the same reason. Do not use chicken wire!
Cages that are not safe for a chinchilla are rabbit, guinea pig and ferret type cages and never put your chinchilla in a glass tank/aquarium for any reason. Also, most cages sold in pet stores are not safe. We have rescued several chins with amputated legs along with chins that have had foot/arm injuries due to being housed in cages that were not appropriate. The reason why the larger wire mesh is not safe for your chin is because chins will rebound off the inside of the cage walls and their foot can go right through the larger wire and cause serious injury. Since it is very difficult to successfully pin and cast a chin's leg, amputation is usually the final result. This is so unnecessary and avoidable by getting the proper cage.
When getting a cage that is galvanized wire, you want to look for galvanized after weld or GAW. You don't want galvanized before weld because they weld the wire joints with lead and if your chin should chew that area it is toxic to them. You also want to avoid any plastic inside the cage and that includes plastic shelving or ramps. I do not recommend wire shelves or ramps that have only horizontal bars no matter how close they are spaced. If you do use a ramp that is galvanized wire, you want it to be square mesh that is 1/2" x 1/2" spacing. Wooden ledges can easily be used for a chin to get from one level to another and they are safer and easier to clean than any ramp.
Brands of cages that we consider unsafe for chinchillas are: Super Pet, Ferret Playpen, Deluxe My First Home, Tubbies, Marshall, Marchioro and Prevue, and any rabbit or guinea pig type of cages.
Since the cage is going to be your single biggest expense as far as supplies, spend wisely and get a cage that is safe for your chinchilla. After all, this will be his home and where he will spend a large part of his time.
Chinchillas like height. They like a cage that has shelves and ledges at different levels that they can jump onto. Always make sure that the distance between each landing surface is close enough that there is no danger of your chin missing his step and falling. They are great jumpers, but you just don't want too much distance between landing surfaces. You can have 1 or 2 wire shelves in the cage as long as you also have several solid surfaces for your chin to stand on if he chooses. I have seen many chins prefer to sit on a wire shelf even when there have been several solid surfaces for him to sit on.
Be careful where you decide to put your chin's cage. Do not have it up against a wall because a chin can fit their teeth through the wire and will chew your wall. Also, don't put the cage too close to curtains, yes I said curtains. Many chins have been able to get a hold of curtains that were hanging near their cage and pull them through the wire and chew them. They are very innovative little critters.
These are usually made of pine, but you can get some made of other chin safe materials. They come in various sizes that you can attach to the side of the cage. You can't lose by having 2-3 ledges in the cage. Chins love them and they can be placed anywhere to serve as a step or seating area. They are great for placing between shelves to get from one level to another or just an empty area you want to fill as a fun spot for your chin to hang out.