heritage chicken bloodlines

I'm looking for information on breeding chickens for bloodlines.
Basically trying to avoid inbred bastardised chickens.

I feel that some of the lesser known Southern African chicken varieties are going lost.

Thus far I've been able to figure out that I need about 50-60 hens in 3 camps, with 3 unrelated roosters to start off with.

Any further information would be greatly appreciated.

I know this isn't much help. I had one breeder tell me to keep the inbreeding at less than 10%.  I have no idea where she got her information from.