First decide what you mean by “meat bird”. What traits are you after? Does color matter? With a white or buff bird you get a prettier carcass if you pluck. With a darker bird you can see the pin feathers. If you skin it doesn’t matter.
Will you be eating the females? Half the chicks I hatch are female so half the chickens I eat are female. So are you looking at traits for both sexes or just males?
How important is size? Many people are obsessed by size but there are only two of us. We can make two meals off of a fairly small hen so we don’t need extra huge chickens. That’s why female works for me.
How will you cook them? You can get varying opinions about at what age you can grill or cook but practically everyone agrees that the older they get the more challenging that becomes. If you are happy with cooking them slowly and with moisture you can get some really nice older birds. If you want to cook them hot and dry, you better process them early so you need early maturing birds.
How do you feed them? If you want a young bird to eat and are buying everything they eat, you need a bird that is at your butcher weight pretty quickly. You want one that gains meat fast though he may not be all that big. If you are happy with an older bird that forages for a lot of what they eat, how quickly and efficiently they convert feed to meat may not be all that important. They could eventually get big without you spending a fortune on feed.
How much freezer space do you have? This is more pointed toward the Cornish X than what you are talking about, but consider if you have sufficient space when you prefer to butcher. Just part of your planning.
How important is white meat versus dark meat to you? Different chickens have different conformations so you can get different proportions of dark versus white.
Are you planning this just for your own use or are you looking to go commercial?
Back before the Cornish Cross were developed, say the mid 1950’s, there were three breeds pretty much used for the commercial chicken meat market, New Hampshire, Delaware, and some strains of White Rock. But with the development of the Cornish Cross, people quit breeding those flocks for meat purposes. Hatcheries very much stopped breeding them for meat so today the hatchery chickens from those breeds aren’t a whole lot different from other dual purpose breeds. Supposedly a forum member is researching if any flocks still exist that meet the general requirements of the original commercial meat bird flocks. I wish him luck but even if he finds them, those don’t necessarily meet my criteria for good meat birds but they would be great for his goals.
I suggest first you decide what you mean by “meat bird”. Then try to get breeding chickens and develop your own flock, whether a mixed breed or a “pure” breed. The better the stock that you start with the easier it will be to reach your goals. Breed the ones that are closest to your goals and eat the ones that are not. If size is a criteria, getting some birds from a show bird flock might be a good start. They don’t necessarily put on a lot of weight early and may not be really efficient at converting feed to meat, but they can be a really nice way to start.
Good luck!
