That’s a very small dog crate. If you put a litter box in it, there would be hardly any room left for the rabbit. Even without a litter box taking up room, that 22″ crate is too small for a rabbit to stay in for the night or for any length of time. The XL size (48″) of dog crate is the recommended size to use if you are going to use a crate. If you get an XL dog crate, you should get the double door model. Otherwise, it can be hard to reach the bunny if it’s in there and you need to get him out for some reason. Or you could use an x-pen. They should be at least 36″ high, so that hopefully the rabbit can’t jump out. When you first bring a rabbit home, it’s usually advised to mostly keep it penned up for the first few days until it is used to a new home, and you know what kind of chewer it may be. That pen needs to be large enough for the rabbit to move around and stand up comfortably. You will need to “bunny proof” any rooms that the rabbit is in, even if you are with him during the day.