Do you really want your chickens to taste like commercial chickens though? I'd go with your dual purpose breeds or anything else just for the tastiness. The cornish x at the feed store and mcmurray's don't taste like that much either. If you're going to pay more to grow it your self and invest the time in processing it, at least make a better product than the flaccid cutlets at
Walmart.
Your best bet is to get freedom rangers or when you decide on a new breed, pick a dual purpose. You'd save a lot of money and time over the course of a lifetime rather than trying to figure out what has taken 3 generations of people to get "right" for the commercial industry. If you can call that getting it right. Cook up your current crosses and call it good, they will be meals of champions, nutrition and tastiness.
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There is a catch-22 to breeding cornish crosses. Your parent stock has to have just the right genetics and you have to have just the right feeding plan to be sure your breeders don't get to bulky to make it to laying age. And once they do, they are bred for their male characteristics, so you don't get the egg laying ability of a normal hen, you get that comparative to a broody hen (stop and don't really want to go). Her body is not set up for laying 200 eggs a year, maybe she's able to do 75.
Commercial breeding operations are not just 3 generations, there are parent stock birds under lock and key 14 generations out. They have to analyze everything. Test and do ratios, lots of math, lots of science. If it weren't for beef by-products in their feed, there is no way the chicken in the store would be affordable with the cost of all the analyzing that goes into creating a breeding program like this. (Not that I think their feed is the key, but my feed bill is a lot higher per lb you can be sure.)