breeder weights

So I have been talking to a lasy who has bought some rats from me as pets. She told me that the rats i've sold her are no where near as big as her others even after months of her having them. She thinks that maybe my rats are dwarfs...? I've never heard of a dwarf rat before. So my question is what are the weights of your breeders. My females range from 6-8 months old right now. The smallest girl i have weighs 240-250 grams before being bred.The smaller girls i have are also my best producers, i have been seeing 15+ every litter from them. The biggest girl is just under 280 before being bred. I have an infertile girl that i've become attached to and shes about 320g. My males are the same age and are all between 400-450g.

Question bump... what size are the smaller breeders?

Those are about the sizes of my breeders as well. 280-300g for females that are not pregnant. 400g+ for all breeding males. Those are good sized rats in my opinion. It may be her rats that are not normal. Either that or they are overfed or come from big genes.

Do the males have to be the 400 gram range to breed? Or what weight are they when they start breeding?
Thanks.

By the time the females were big/old enough, my males were 300+ and they have just grown from there.