I haven't raised chickens for meat, that is, on purpose. But I did hatch eggs under broody hens, so sexing them ahead of time was pretty much out of the question. I have found that if you set a broody hen on 12 eggs, she will hatch out 9 cockerels and 3 pullets. I think that is b/c the cockerels grow into roosters and they protect the hens and loose their lives in the process. So, nature gives more males than females. The ambient temperature may have something to do with the m/f ratio too. I think that alligators are the same, sex is determined by the temperature of the egg mound where the eggs are incubated. Chickens are considered related to reptiles, yes?
What to do with all those hormone-rich cockerels? Well, they were the meat birds! At one time, I found a local breeder who had Dominique eggs for hatching. They were wonderful birds. Not the best egg layers but very calm birds and they grew pretty large. One of the cockerels (at about 8 weeks) weighed in at 5# after slaughter. When the hens had matured past egg production, they were slaughtered for stewing birds. Some hens were 4-5 #. Compared to Red Sex links, that is a great weight. They clean up very nicely, skin is white and their breast, legs and thighs are larger then most birds.
My friend was impressed with the Dominiques that I hatched and their progeny. He ordered Dominiques as meat birds from a hatchery. These birds were puny, not very hardy and none weighed more than 3-4 #. If you can find a local Dominique breeder and can get some hatching eggs to set under a broody hen, these birds would be a great choice for meat birds. They may need to go 8 weeks for best result.
Kosher Kings are a great bird of choice. They do need more time to mature before slaughtering and can be pricey. But they are fantastic at foraging and if you have the acreage, they will be happy in a portable house with good fencing to keep predators away. I have heard they can weigh up to 6-7 #.
So, instead of six weeks for (poor, sad) Cornish crosses, Kosher Kings may need an additional 4 weeks to get to good weight.
I never would choose Buff Orpringtons for meat birds...they are so sweet and easy to manage. Great egg layers and great with kids, even the rooster! Black Sex Links were a good idea, any that I had slaughtered weighed in at 4-5 #. They were older layer hens. But if you can order only male birds, they will weigh in at at least 5 # at 7-8 weeks. A few weeks more and they will pay their grain bill.
Then there are Dorkings. These birds are very close to wild in nature. But they grow into very nice meat birds. I think they are more available out in the mid-west rather than on the east coast. Again, finding a local breeder rather than buying in from a hatchery will give you a better product in the end.
I was Certified Organic for my poultry, this made it more costly to produce meat and eggs. But worth it since I seldom had any sickness in my birds. I feel if you were to look into what is in conventional poultry feed, the ingredients may shock you. It is permissible to use soiled bedding as a filler in conventional poultry feeds. And folks wonder how the bird flu is spread? A no-brainer. Feeding animals waste products from other animals should be outlawed. But it is one of the ingredients. Be aware of what you feed your animals if you intend to consume their products.
I don't know if this information helps. I hope it does!