A really thought provoking reply Sarah, hope you don't mind if I take the time to respond to some of your points.
sarahc said:
Its definately a trait of some varieties,siamese being the obvious one
This is interesting, as siamese rats in the past have had a poor reputation for temprament. Wonder if this is also true for other animals with that patterning?
Its also a normal male behaviour so not all bucks that do it can be condemned.
I have buck rats here that won't live with other bucks and would show aggression to them, for the pet owner who wishes to keep buck rats together the problem is easily solved by neutering usually. I would not condemn a buck for that kind of behaviour, but if he was aggressive to does he would be useless as a breeding animal, and I would not personally want to keep an animal that was overlly aggressive to me. I am the alpha
The siamese I had that did it was an extreme case and was dispatched.I wouldn't have passed his progeny on to be pets. Personally I wouldn't pass bucks on as pets at all,does are so much more problem free.In that respect they don't really compare to rats.I think rat exhibitors are more likely to pass their surplus on as pets in any case and less likely to cull them?
Yes, there is a market for both buck and doe rats as pets, so there is a choice to offer surplus to pet homes. I think if buck mice did not stink so badly more people would like to keep them as pets as they seem to have more character then the does

But with there being no outlet for them I fully appreciate there is no point in allowing a doe to waste energy raising more then are needed by the breeder.
As far as being a show animal, does not bucks fit the ideal and are far more likely to be shown so its not much of a problem really.
This is a huge difference between the rat and mouse fancies, and one that is very interesting to learn of. With rats, there are seperate standards for the types of bucks and does, so although they are judged in the same class for their colour/markings etc an excellent doe would not look anything like an excellent buck in body shape. In many varieties, the does will be the better show animals mainly due to having shorter coats and better colour generally, but rex and siamese are 2 notable exceptions.
Some of the very nice docile bucks can be a problem to get breeding.Its a case of balance between being butch and not to fierce.
I completely agree with this, one of the challenges, keeping the balance between being tractable and being up for the job
