Yes, if you're not a breeder.
NO!
Spay is the sterilization of female animals. (Removal of uterus) Neuter is the sterilization of male animals. (Removal of testicles)
6 months
Yes.
The stray kitten is most likely something much more mundane such as an irresponsible pet owners that don't spay and/or neuter their animals.
If when you use the word "Fix" you mean spay or neuter, then the answer is yes. Your Veterinarian can spay or neuter a Chinchilla. Call your Vet to make an appointment to do this.
Only with most of their dogs and cats. They don't spay any of their female livestock, but will neuter or castrate the male livestock that are undesirable for breeding.
You spay a female dog and cat, you neuter a male dog and cat.
It is called Spay or Neuter
Yes.
Well I have a rabbit and its not spayed or neutered, and its a little bit aggressive. It growls whenever I try to take it out of the cage.
NO! When pets aren't spayed or neutered, they have more serious behavior and health problems. You have to spay or neuter BOTH pets.