The majority of hatcheries we but from are mass marketing birds that pretty much follow breed standards at a low competitive cost. They generally use the pen breeding method where they may have about 20 roosters in a pen with maybe 200 hens randomly mating. This ratio is to keep fertility high and maintain genetic diversity. They want the eggs to hatch. They are mostly family type small businesses and usually have someone that understands genetics that selects which chickens get to breed. They generally select those breeders by breed standards but the nature of random breeding is not going to breed show chickens, including size.
Breeders on the other hand carefully select which specific rooster gets to breed which specific hen. They carefully match characteristics to enhance the chances of getting a champion show chicken. They have their own techniques to maintain genetic diversity, often a spiral breeding method. It takes a lot of expertise and work to raise enough chickens to an age that they can determine which are their keepers. It is not easy and it can get expensive. These hatching eggs or chickens are not sold at mass market prices if they are sold at all.
One of the traits the breeders typically breed for is size. Show chickens are rewarded for being fairy large. Weight is a breed requirement that hatchery chickens usually do not meet. If size is that important to you in your meat chickens you will be better off getting the more expensive breeder birds as your foundation stock. It will make a huge difference. But when you start selecting which birds get to breed you need to know enough to know which birds to eat and which to select as breeders.
Breeders on the other hand carefully select which specific rooster gets to breed which specific hen. They carefully match characteristics to enhance the chances of getting a champion show chicken. They have their own techniques to maintain genetic diversity, often a spiral breeding method. It takes a lot of expertise and work to raise enough chickens to an age that they can determine which are their keepers. It is not easy and it can get expensive. These hatching eggs or chickens are not sold at mass market prices if they are sold at all.
One of the traits the breeders typically breed for is size. Show chickens are rewarded for being fairy large. Weight is a breed requirement that hatchery chickens usually do not meet. If size is that important to you in your meat chickens you will be better off getting the more expensive breeder birds as your foundation stock. It will make a huge difference. But when you start selecting which birds get to breed you need to know enough to know which birds to eat and which to select as breeders.
I have no actual knowledge of the details of any of this. The first time someone other than Henry Knoll selected which chickens got to breed they were no longer Henry Knoll's birds. That's why I made my comment above about needing to know which ones to breed. That's not just breeding for traits, that's breeding for genetic diversity. As I said, this stuff is not easy or cheap.when I saw increased weaknesses in the 2024 than any of the previous 3 replacement batches (crossed beak, curled toes, angel wings, greater variability in size/weight, aggression, poor fertilization) I sadly realized it was clear these were not the product of Henry Noll's meatbird selection