I agree with Luckies on her explanation of breeding rats. Yes I do realize that there is a problem with rats not having homes, so far I have yet to find one in a shelter in Tucson (and trust me I look often) but I have seen a few in the Phoenix area. However it's not like going to the shelter where you can adopt a healthy dog or cat. Most of the rats that end up at a shelter came from pet stores and not a good breeder. These rats almost always have myco (if you search on google you will see that a large amount of rats have myco) or will develop tumors at a very young age. Good rat breeders work hard on the health of these animals so that there will be lines of rats that don't have myco and aren't prone to tumors. I think people who have never owned rats don't really realize just how common it is for these little guys to get sick. It seems like rats rarely die of old age, myco or tumors usually get to them first.

Overall I do agree with good and responsible breeders, how ever I know that the majority of breeders out there aren't very good.