A good rattery has a goal in mind when breeding, instead of just multiplying rats without a clear breeding goal. In general I aim to improve the pet fancy rat as a species and hopefully gain some progress, but I also make some personal choices.
In my opinion this is the most important goal for a breeder, because however healthy and pretty they are it is all pretty useless if they aren’t nice pets. Of course it is important the rats are tame, so they should not be skittish or naturally scared of people. They also need to be social to other rats, as they are social animals and they should be able to have a happy normal life with others of their kind. (Extreme) behavioural issues are not acceptable.
Apart from those basics I personally favour rats which love getting attention from their owners. Rats which like to cuddle and play with you rather than only minding their own business. This is of course entirely personal, but I do aim to breed rats with personalities like these.
Of course any good breeder wants to breed healthy animals. Sadly rats are generally not very robust animals, they don’t live very long and are susceptible to all kinds of health problems. My main goal is te create a line with a sound health by breeding away from recurring hereditary problems. I would also like to improve the life span, mainly by getting rats to reach a nice age consistently rather than breed a few ancient rats.
I will never claim my rats are completely health problem-free as no strain of living beings can be completely free from all issues. However I take trying to breed healthy animals very seriously, you can read about how I aim to realise this in my Breeding Ethics.
Though build is technically an aspect of the rat’s appearance, it has a lot to do with health. Badly built animals are often less healthy as well and can even get serious health issues. Small abnormalities can cause big problems if you don’t keep an eye on it and let it get worse each generations.
I think it is important to aim for a strong natural build which supports a healthy individual. Bad aspects will be corrected instead of being bred into the line by choosing rats with builds that complement each other. It is one of the things I keep in mind when selecting breeding rats.
Unfortunately we do not have a lot of shows for fancy rats in the Netherlands and even less which are safe to bring your rats to, but whenever possible I try to enter my rats to have their build assessed by a judge.
Even appearance plays a role in breeding, I am not afraid to admit that. The goals described above are more important, but I do not believe we should breed all kinds of varieties together indiscriminately. Some varieties are more robust than others and stacking different varieties also lowers the general health. Therefore I breed only a couple of varieties.
Regarding the coat colour I favour blue shades. Fancy rats have two genetically different “blue-mutations”: Russian blue and American blue (in the UK: British blue). Both are visually appealing to me, but because American blue is harder to breed right there are only few American blue rats in the Netherlands. Therefore I aim mostly for Russian blue with the possibility of Russian silver, which is a combination of Russian blue and American blue.
By adding agouti to the line I hope to improve the general build of the rats, as such I aim to breed Russian blue agouti and Russian silver agouti.
Besides colour rats van also have white markings on the coat. Personally I do not care much for ‘perfect’ markings, but I like how diverse markings can be. Hooded and berkshire markings are pretty much my favourite, not only because of the markings themselves but also because they are pretty much problem-free unlike (some) variegated markings.
I hope to keep hooded and berkshire markings in my line, without a lot of unmarked rats.
Coat and ear type
I do not care much for coat types, especially as many of them are rather new and come with health issues (at least in the Netherlands). Most of my rats will be smooth coated, though rex-coated kittens are a possibility.
I prefer top-ear over dumbo ears as I like the look better and dumbo eared rats tend to have slightly different build heads if you don’t breed them well. For simplicity’s sake I try to avoid breeding dumbo.