Okay, after some searching, I did find someone on BYC who's interested in CPGs.
https://www.backyardchickens.com/threads/cotton-patch-association.593043/
Then you need an SOP book, and advice more experienced than mine. What breed are you trying to preserve? If it has an active thread on BYC, you should get a lot of very good advice there.
EDT: I'm an idiot who can't look at thread titles. Sorry. Give me a moment, and I'll try to be more helpful.