If you bought from a feed store, you HAVE a huge genetic diversity. What will happen over time, is that you loose efficiency in your flock. When considering breeding, low quality birds x low quality birds = lower quality birds. It is slow, as in over ten years, but you tend to decrease your longevity, egg production, thriftyness and meat production. Centuries ago, mankind realized by controlling the mating, you can increase production, and animal husbandry was started.
In animal husbandry, the cheapest way to improve a herd or a flock, is through tthe male. So if you start with cheap birds, and you want to raise your own, don't use your own rooster. Cull those and look around and buy a rooster from a good breeder. For example, mine were just riff raff hens. This year, (and this is year 7 for me) I decided to get a pretty good rooster. I spent $20 for a rooster! Gasp. The thing is, is people always have too many roosters, so they are easy to get.
Now I am just hatching out my chicks out of him. So far I am pleased. I wanted better colorization to blend in to the prairie more for better luck with predators. And I wanted more heavier birds for the stew pot. I am using a Bielefelder rooster. This is a German breed that I accidently came on.
My plan is to breed this rooster back to the daughters, and then the following year, go looking again for a high quality rooster of the same breed.
It is slow, by next year, I will see if I did get what I wanted, or if I really like these birds.
This is a fun hobby.
Mrs K