A little about the history of the Cornish Cross, Cornish X, Cornish Rock, or whatever you wish to call them. They go by different names in different countries. The Cornish X were developed in the middle of the 1900’s by selective breeding. There are no GMO’s or anything like that involved. Genetics experts selected which chickens to breed to create them. The selection has improved since then but by the 1950’s the Cornish Cross was so efficient at feed to meat conversion that people stopped breeding Delaware, White Rock, and New Hampshire as commercial meat birds. They just could not compete economically.
Growth hormones are not involved either. Growth hormones have been banned in chickens since 1959. When you see a package of chicken advertising in big letters, no growth hormones, that’s true but also misleading. Since they are banned no one else uses them either. That’s not true of some other meats but it is true in chickens.
The genetic formula to create the Cornish X is a top secret with the different poultry producers. Each company have their own breeding stock. They started out with Cornish to improve the breast meat portion as part of the genetic mix. White Rock was probably in the mix to give lighter feathers to improve the carcass appearance and other genetics. Other breeds may have been used. It is not a simple cross of Cornish and White Rocks. It involves many generations of selective breeding by experts. We cannot create them on our own in a couple of generations.
The current Cornish X is a four-way hybrid. They maintain four different flocks to produce the breeding that will produce the broilers. Each of the four flocks produces a distinct grandparent of the broilers. One flock produces the hens that will lay the eggs that become the mothers of the broilers. A different flock produces the roosters for that mating. To flocks produce the breeding birds that will produce the fathers. So you have two more flocks that produce the parents of the broilers, then a seventh flock that finally lays the eggs that hatch to become the broilers. You are not going to reproduce that in your back yard.
If you read through this forum you can find several posts or threads where people have tried to keep the Cornish X to breed. Some succeed but most fail or are disappointed. The broilers are bred to convert feed to meat so efficiently that often by the time they are 8 to 10 weeks old they have grown so big that their heart has trouble keeping up or their skeleton just can’t support all that weight and they break down or die. They can also be too big to breed naturally so you might have to resort to artificial insemination. The way commercial operations get around that is that they restrict the feed of the parents so they don’t get as big. It’s a pretty fine balance of feeding them enough to keep them healthy and productive laying hatching eggs versus feeding them too much so they develop medical problems. These show how a certain commercial operation in Canada handles this. It can dispel many myths about the broilers.
They are hybrids and will not breed true but they will pass on a lot of the genetics for fast meat gain. Many people try crossing the broilers with other breeds to retain some of that fast growth but slow it down enough that the chickens can survive and breed. Some have been happy with their results, some have not.
. First rule of the chaos theory!
