Bigger is always better when it comes to your small animal's home:
Rabbits need relatively large cages, as well as several hours outside their cage each day in order to get enough exercise. Large rabbits need at least 5 square feet of cage space.They should also be allowed to explore in a safe room for a period of time during the day so they can stretch their legs and play.
Guinea Pigs are social animals and prefer to have another Guinea Pig(s) as a companion(s). Their cage should be at least 50''L x 24"W x 18"H well-ventilatedand have with a solid flooring. Some guinea pigs may enjoy small, safe ramps and multiple levels.
Rats require a large cage. They are active and need space to run, climb and explore. The cage should be diverse and divided into several three-dimensional levels with climbing opportunities, exercise wheels, hiding places and plenty of things to gnaw on.
Hamsters need a lot of room (especially at night), so buy as large a cage as you
can to provide your hamster(s) with suitable enrichment (such as small boxes
and tubes, exercise wheels and wooden chew blocks). Most hamsters are solitary animals, and can be aggressive towards other hamsters. Dwarf hamsters can be housed together. A glass aquarium is an excellent choice because it offers no bars for the animal to squeeze through. It is easy to open and easy to clean. However, it’s important to get a well-fitting mesh top to keep your hamster from escaping. As long as the top allows air to freely pass, ventilation isn’t an issue.
Gerbils do best in aquariums. They are inexpensive, easy to clean and allow you to observe your gerbils more pleasurably. Most importantly, the gerbils cannot chew through these enclosures. If you decide on an aquarium, you will need a mesh or wire lid securely fitted on top to provide air circulation.