If, and this is a big IF, you choose a traditional, dual purpose bird, such as a RIR, BR, WR, Del, etc, the older tradition was to buy/hatch straight run. 'Few old time hatcheries "sexed" these chicks. The small flock keeper would raise them together, feed them the same feed, of course. Then, at 16 weeks, the cockerels were now obvious. Their large red wattles and combs, pointy feathers and upright stance gave them away. Some were beginning to crow.
The cockerels were harvested, sometimes the pullets as well, but not as frequently. These young "fryers" were tender and made the greatest fried chicken in the universe!!!!!
Today, folks keep super laying hybrids for egg laying and super fast growing hybrid CornishX for meat birds. Still, there are many folks who still raise chicks to be "fryers" the old fashioned way, using old fashioned, common, dual purpose breeds. Hope that helps. We've been doing this for over 50 years. Those are "fryers" in my avatar from circa 1959.