When talking with most "older breeders" you will find they are referring to standards used for standard gray chinchillas, because they were the most prevalent color of chinchillas being raised, and they were being raised for fur, not as pets. {The standard gray chinchillas that lived in the wild were often twice the size of most chinchillas of today.}
The 'standards'/'general rules' set by the breeders to go by were based on the age, health and size of the chinchilla ... 500 grams is often considered a minimum "safe breeding weight" because that weight was usually not reached by the standard gray chinchillas until the chinchilla was old enough/mature enough, and developed enough to safely carry and deliver kits.
Mutation chinchillas came along later, but the same age and size "standards" were/are still being used. Most feel it should still be the standard/rule because that weight is usually not reached until the chinchilla is old enough/mature enough, and developed enough to safely carry and deliver kits ... not to mention, a larger chinchilla with a good build and good fur is a sign of a healthy chinchilla ... this is what a breeder should strive for ... so that the chinchilla will have a future and not become extinct due to bad breeding. What so many people/older breeders do not explain to new breeders, is that is it is not just the actual weight that has to be considered, but, the maturity and bone structure that is a huge factor in the safety and health of the mother and kits. A female chinchilla must be "large enough" in the pelvic area to be able to safely deliver kits. There is a way to "measure" the size of the pelvic ... it is by using the size of the thumb to check the size of the pelvic area/delivery canal of the soon to be momma chin. {
Aha-Hah, but not everyone's thumb is the same size either ... well ... at the time this was (and still is) practiced, it is the size of a grown man's thumb, not a child's or a woman's thumb. }
As a general rule, the smaller the parents, the smaller are the kits born to them ... and ... the lower the birth weight ... the less likely they will survive.
Smaller chinchillas are sold as "pet quality", not as breeding quality ... due to the fate that would result for all chinchillas, should breeders continue to breed small chinchillas and do nothing to try to strengthen the gene pool.
Ebonies are usually small, due to the constant breeding of ebony to ebony (most people are not patient enough to work at it and help the line become stronger over generations - this would be much better in the long run - but to many want the "instant gratification" of the dark ebony kits immediately).
To do this, you will need several ebonies, as not to breed back to the same line over the generations.
IF this ebony has
good strong fur, a
blueish tint (no hints of red tint), and is blocky built ...
and you really want to breed her, I would use a
pure standard gray that is
slightly larger than her.
I would do the same with several other ebony/pure standard gray pairs and breed each new generation of standard gray/ebony carrier to another new generation of standard gray/ebony carrier or hetero ebony to hetero ebony ... each time breeding to a slightly larger pure standard gray or large hetero ebony. Over several generations (and years) you should be able to develop larger ebony chinchillas. This is the longer route ... but the safest and most prov-en method to succeed.
In the wild and as a general rule, the female is larger than the male ... As Jamie said ... in doing this (large male to small female), there is also a chance that the kits born to small females with larger sires, will often produce kits to large to deliver and you can loose mom and kits.
Jo Ann
Each new journey begins with one step ..
Slow and steady, goes the patient traveler ...
To his desired destination.
The pace of the traveler who is in a hurry ...
Oftens finds himself by the wayside ....
Without a goal that can be reached.
