I am not exactly sure. When my mother had her 2 guinea pigs, we threw a rabbit in their. She was small at first and grew bigger. Our male guinea pig (Getting no action from the female) attempted to mate with our rabbit and failed. Upon trying more, we later found our rabbit bite part of our male's guinea pigs ear off!!
I wouldn't suggest it, especially if the cage is smaller and cramped, chinchillas can be big.
I would not put them in the same cage. Your guinea pigs will have different needs than your chinchilla. Guinea pigs tend to be a very defensive animal, meaning that they tend to try and protect themselves from anything they are not familiar with. Guinea pigs also tend to be the type of animal who is more likely prone to stress when around familiar surroundings. They need plenty of room and familiar surroundings. Too much stress can cause your guinea pigs to become ill or even die.
I would highly suggest getting a separate cage for the chinchilla.
NO...lol they are completely different animals with different needs and eating habits. Also, i think it would be much too crowded with SEVEN inhabitants... xP they might fight and kill each other ...
Chinchillas are extremely sensitive animals towards stress and putting them in the same cage with guinea pigs is definitely NOT a good idea.
A chinchilla needs a lot of space to live in as they like to run and jump. The minimum space for a ONE chinchilla is 35 x 35 x 35 (90cm) but preferably more.
For additional information I suggest you read up on the pet you intend to get before you do so: http://www.chinchillaclub.com/mag1/0802health.html
There is a 50/50% chance that your guinea pigs or chinchilla could contract a disease from each other and if your not careful the disease could be fatal.
so no it's not a good idea that you put them in the same cage together.