I've been going through and trying out different rat sites to see if they are hateful towards feeder breeders or if they offer polite and genuine advice without letting their personal opinions sway them too far. The outcome isn't exactly a positive one for the majority of communities (the blacklist is forever long) but I seem to have found one community that dig into the questions and answers them in the best way they possibly can with facts rather than the fluff of opinions.

I've been a member of this particular group (it is a closed group) for over a year now. The community is accurate, friendly, fast-paced and (relatively) open minded. They are prime examples of what the rat fancy should be and are there to help improve rats as a whole rather than pick one another apart with politics. The primary focus is genetics so a basic understanding is somewhat required to join in, but they will help with issues like: breeding for respiratory resistance, how to improve the type (build) of your rats, how to surface recessives through different breeding methods, determining if your lines carry MC and how to back breed so you can accurately check and many other subjects that are just too complex to list here!

The group is called Serious Rat Genetics, Breeding, and Ownership and I highly recommend it for anyone who genuinely loves their feeders (or pet lines!) and wants to improve them as a whole with people that are well educated.

Group Information
"This group is for all breeders - active, aspiring, retired or otherwise - that have a serious interest in genetics. This is not a group for "I bought this rat at a pet store, what color is it" posts.
This group is also for pet owners, rescues and anyone else that would like to learn about genetics and husbandry, that can be civil and willing to listen.
Very little will be censored in this group. If you don't want to be called a back yard breeder, don't be one. Being an unethical person is indeed enough to get you banned. Anyone that is willing to learn and can take the heat is welcome. Anyone that is stuck in their ways or can't handle other people's opinions can go elsewhere - there are plenty of feeder breeder groups out there, as well as groups that baby everyone.
When you join this group, please make sure to look at our rules doc. We have rules that you don't find in other groups (such as not being allowed to post random cute photos and not deleting posts). It is pinned to the top of the page, and can also be found in the docs section."

If you are respectful, reasonable, ethical and humane, this is the group for you. This group is aimed at pet and show people, but if you read the rules and adhere to them then it should not be an issue for you to join.