I'm late to this post too it seems.
It took 3 years to build up the flock to get the birds we needed in order to provide 2 people with meat and eggs year round. Next year we should be eating like kings.
Our goal was 72 extra roosters per year. That means that at minimum, I have to hatch 144 eggs. So I need to set at least 160 in a batch to account for duds/quitters. Then there is the space to manage that many, so I break the years hatch down to quarterly batches. 60 eggs set every 3 months, as close in age as possible so that they can live together. A batch gets sorted every couple of weeks, moved to a bigger area each time until they hit the finishing coops.
The finishing area has a 1/3rd acre pasture that the boys go to at 3 months old. All of the boys from a batch, sometimes with a good cockerel who's older and acts as leader bird and trainer. At 16 weeks we start sorting through them, mean ones first who want to cause drama in the flock.
We do Bresse and Marans along with some hybrids. The breeding boys are selected from the grow out area for having better size/shape/type/temperament/health/vigor when compared to their peers. If they're better than their sire, the sire gets replaced.
As a rule we don't eat the girls, they're either breeder prospects, layers or sellables to offset the feed bill. Where we live you can barely give away a rooster for free, so to be a breeder we have to have a male management plan. I have to keep all of a hatch, for the most part, until gender is known. We don't ship birds or eggs or anything, everything is local.
Hatching eggs need to be about a week old tops for the best performance, so if I need 60 eggs for a batch then that's at least 10 hens in active lay making "hatch worthy" eggs. I have 45 girls at any given time. Who knows when a bird will take a break or lay wonky or otherwise not make the perfect hatching egg. So we have sellable eggs, house eggs, dog eggs and hatching eggs. 7 roosters "at work" at any given time, not counting cockerels in grow out.
Breaking it down into batches makes it easier to manage, in terms of feed bill, brooder/pen cleaning, keeping the fresh water coming... we raise Turkeys too. I would rather raise some all of the time instead of trying to raise them all at once. What if the power goes out and I lose everything in the freezer? Dual purpose heritage types "store on the hoof" until about a year old, if needed. Sometimes you need that full year to make a breeding decision, depending on what all you're breeding for.