Most breeders of pedigreed rats will not adopt out to people without a non-breeding contact (that in many places has to be notarized) or will only adopt out breeding rats to:
A) People of good standing in the rat community (whether adopting, breeding, showing or general contributions)
B) People they have mentored or their mentor knows.
C) Other show breeders with experience and connections to good breeders that can give legitimate references.

I am an aspiring show breeder, working under my mentor, and I am only able to get rats from her line for breeding purposes because she is my mentor and I do not cull out of that line. These rats are black self. You usually have to "graduate" to different varieties to gain trust. My mentor knows I also breed feeders but I am not allowed, nor do I want to, mix the lines.

If you cull at all or are purchasing these rats to add to feeder lines, I would recommend you go see a feeder breeder. Generally speaking, show breeders will not adopt out to feeder breeders. (Ruins their lines and/or credibility in the community 99% of the time.)