You will not taint the breed if you follow this simple process many use.haven't decided yet if I'll keep the ebay group off to themselves so I don't taint the breed. We'll see, it would mean a different coop and run for them. probably more of a pain in the butt than it's worth
When you think you want to have more chicks,,,,, and bred a certain way, you separate the choice hens for about 3 weeks with no roosters. You then place desired rooster in with the hens of your choice. The eggs will be fertile with that roosters genes. Carefully incubate only those eggs ,,, and you have your UNTAINTED chick breed. Once you are finished hatching,,,, you let all chickens socialize together again.
Alflock is a good choice of feed that I have used for a very long time. Make sure that you have oyster shells available free-choice. You only need Chickstarter for baby chicks,,, and use crumbles. (pretty sure that is only way it comes)
I use Alflock because some of my hens do not lay frequently since they are seniors. I don't have any roosters, and cant, due to local regulations.