If the cornish is a good meat bird, why are they always crossed with other breeds? What does each half bring into the equation?
They aren't always crossed, you can get pure cornish chicks. It's just that the cornish x's are super fast growers, that's why more people go with them. The regular cornish don't grow any faster than any other bird, in my understanding.
The cornish meat bird is a "cornish x rock". It's not actually a cornish. The fast growing meat chick is a F1 hybrid between a white rock line and a white cornish line which have been perfected over the past 60+ years. So I guess to answer your question, people call them cornish for short, which in reality, are completely different than the breed cornish.
The White Rock based half of the cross are good layers, so they provide lots of cheap eggs. There are also probably fast maturation Genes from this side. The Cornish Rooster provides the heavy muscle genetics. If a Cornish hen was used, the eggs(and chicks) would be more expensive. Actually, I suspect modern X's use at least two generations(F2) of hybrids There would be 4 sets of inbred lines. Two would be crossed to provide the Cornish rooster and the other two the Rock hens. Hatcheries buy 1st generation cross roosters and hens for breeding stock and incubate the 2nd generation eggs. The result is lots of eggs with genetics to eat nonstop, grow like crazy, and put on lots of muscle with(inadvertently) little ability to reproduce or "think"!
My impression was that there have not been any pure Cornish or pure Rock birds involved in commercial broiler breeding programs for, like, *many decades*?? That Cornish and Rock were used to create the original stock but now all the parental lines are maintained as "what they are", not re-created every generation? Pat
Quote:That's true Pat, there are quite a few Perdue chicken houses around our area. It's a closed operation, they mill their own feed to their specs, hatch and raise their own birds. They have been bred to "do the best" with their methods. Steve in NC
Yep, the strains of white rocks and cornish are just in the genetics. The percentage of which is not known.... They constantly cross differerent males with different females keeping the blood lines fresh. It's hard to say what the typical white broiler is made up of today. The reason why they cross the two was to get the best of both worlds. The rocks where selected because of their skeletal structure (big, tall, broad,) also noting they are good egg layers. The Cornish are known for their meat to bone ratio.... cornsih are very compact birds for their short squaty size. Thick bodied... When you cross the two you get hybrid vigor.... getting a bird that outpreforms both the female and the male lines. That's true with just about any cross you do... it's a fresh set of genetics to say the least. Over the years they have made male lines and female lines, giving like someone stated an f-2 product. There is grandparent stock and also parent stock. And there are so many ways to mis match these lines. Giving an end product of very good genetics and a very fast growing bird. Bottom line is that it's way more than just a white rock and a cornish but it's how it started. Cornish are mainly used for meat strains becuase they have wide bodies and lots of meat compared to bone. Giving a very appealing carcass for the table. Crossing a bird like this with others just makes a better bird in the long run... if you select the right qualities when breeding.
The commercial Cornish X is not the result of a single Cornish x Rock but several crosses to produce a 'climax' hybrid that will not breed true. This is a highly guarded 'recipe'. Try finding a pure full size White Cornish that isn't a bantam hybrid. Try finding a pure rose combed White Rock-near to impossible. The list goes on and on!