Elizabeth that runs this site has done a number of good things. One is she takes genetics to be the serious topic that they should be (what every good breeder should do) and has charted eveything so carefully that i hope i repeat this correctly...there is some genetic trait between the dumbo ears (or another special thing her rats have) and a birth defect that people suffer from. A specialist came from Japan and took several of her rats and her careful plotted out genetic information to help them try to eradicate this birth defect. That may not be exaactly right but close enough to see how responsible she really is. She is an awesome woman.
I know her through my friend Kelly. It has taken all my will power not to get one for they are simply devine. My two dogs are more then i should have and all i can gaurantee good health care for so that stops me right there. (the humane society doesn't see rats) darn it.
There are several things rats can be prone to if they are not carefully bred. One is a gastro problem and of course there is always the cancers. So by carefully breeding a good rat breeder tries to keep the gastro problem away and reduce the risk of cancer and that is why I think it is important to buy from someone like her and not from your local pet store where they are mostly reptile food and no one cares where they came from.
or how they were taken care of before they came there. I have seen Elizabeth's setup and people should have it so good.
as to the odor
if kept on a peat base bedding which is wayyyyyyyyyyyyyyy better then wood shavings or cedar which can make them sick, it will reduce the urine odor greatly and neutering will help with the male odor as well. Kelly has her rats somewhat litterbox trained. She took a bookshelf and made them a three tier hotel where they could go from one shelf to the next with a litter box in the corner of each by covering the shelf with hardware cloth and cutting a square hole through each laminated shelf. Elizabeth has these extremely fancy tiered cages that are easy to clean.