In Australia we are lucky enough to have some wonderful people who dedicate their time towards looking after and finding loving homes for our furry little four legged friends. Rats are surrended to them for various reasons - mistreatment, accidental litters (unfortunately the majority of the time it is due to irresponsible pet stores), loving owners who are unable to keep them for whatever reasons and so on.
Be aware that rodent rescues DO NOT provide their rescues as feeders. Do not bother to contact them if you feed mice or rats to other animals. Rats are intelligent, sensitive creatures and deserve to be treated with the same love and respect we give our other pets.
If you would like to find out more about adopting or make an enquiry please contact the relevant link below.
Brisbane Rat Rescue: http://furry.org.au/brisrats/about.htm
Tasmania Rat Rescue: http://olivereindeer.googlepages.com/home
Western Australia Rat Rescue: http://www.prrr.org/
There is also a yahoo group for aussie rodent rescue which you can join.