My hatchery stock Buff Orpington cockerels started reaching 5 lb live weight by 16 weeks for the better ones. Others took longer. I don't process in large batches, so it isn't an issue for me. I like to fry them, so all were processed by 24 weeks to ensure tenderness, regardless of weight. Some will say this is too long for fryers. I soak overnight in buttermilk, and pan fry slowly. I've been pleased with the results, but I don't mind a little texture. How you prepare, and when, is a personal thing. They were fed 20% protein their entire lives, and raised on grass. They aren't very efficient cost-wise, but that isn't my goal. I like the flavor, so I raise a few every year and consider it more of a delicacy, as opposed to commercially available chicken that tends to be more of a boring, commodity item. I kept 8 pullets from that batch. They are one year old today, and one is currently broody. Your results may vary.