Broilers are chickens that are reared specifically for meat. They were bred to get the most out of their feed so that they reach the best slaughter weight quickly. The meat yield to live cost ratio is a key factor in how desirable they are.
Commercial breeding pyramid, ©BHWT
Resulting heavy birds are prone to hock lesions, commonly referred to as ‘hock burn’. These pressure sores may have formed because the skin on the hock hasn’t changed enough to handle birds’ heavy bodies, which keeps them from moving around much (Price, 2012). High-protein diets have also been linked to more hock sores. Using good, dry litter helps keep the problem to a minimum.
The process of breeding broilers begins with pure line breeding stock. There are only three or four companies in the world that hold these pure line birds. All of the chicken we eat today comes from these companies.
Their eggs make Great Grand Parent Stock (GGPS). The pure line birds are kept in high level biosecure hatcheries. Birds classed as GGPS then go on to produce Grandparent Stock (GP) who then produce Parent Stock (PS).
In the world, about 3% of the chicken population is made up of PS, GP, and GGP stock, which are all known together as Parent Stock. The US supplies around 25% of world GP stock. This is known as the primary breeding sector, and 417 million PS are produced every year. (Aviagen, 2011).
A single pure line or pedigree level hen could have 25,000 offspring that are used for breeding and go on to produce 3 million broilers.
Pedigree stock is carefully checked to see how much oxygen is in their blood and what kind of bones and muscles they have. The industry is also putting a lot of money into genomic research to find ways to improve performance even more, since physiological selection doesn’t seem to be coming to an end.
The parent stock are then used in broiler breeder farms to make fertilized eggs. Their lineage will look like the diagram above, with GGP hens mating with broiler breeders to make our Sunday roast.
The males and females of parent stock come from different genetic lines or breeds, and the chicks they have are called hybrids. Every hen is expected to lay 150 hatching eggs over a 34–36-week period.
The gender of the chicks is governed by the female, (whereas males determine gender for mammals).
Many times, the number of males to females should be equal. But, in parent stock production, this doesn’t always happen. This is because male embryos make more heat than female embryos. Since embryos can’t handle too much heat, males are more likely to die late in the process before hatching.
It’s interesting to note that the 50/50 balance is kept when the number of male “late dead” is added to the ratio calculation.
On the other hand, layers act the opposite way; females make more heat, which means they have more “late deads” before hatching. (Poultry Performance, 2021).
Hybrid day old chicks are placed in rearing houses with specialist brooding equipment until 18 weeks of age. It is important to keep an eye on the chicks’ weight while they are being raised because birds that are too heavy don’t lay as many eggs. At this stage, males and females are raised separately because males grow faster. Separate feeding also makes sure that males and females have the same body weight.
When the birds are 18 weeks old, they are moved to broiler breeder laying houses, where they are raised with both male and female birds. Hens and roosters mate; usually, there is one male for every 12 females. The roosters fertilize the eggs, which are collected twice a day.
As the flock gets older, younger roosters will be added to keep it fertile, and the ratio of males to females will be managed so that every hen mates every two to three days. The hen can store sperm in her oviduct, but she will only be fertile for three to four days after mating.
What Is Grandparent Stock In Poultry? A Detailed Guide
When it comes to the complex world of commercial poultry farming, there are many terms and concepts that can be confusing for those not deeply familiar with the industry. One such term that often raises questions is “grandparent stock.” But what exactly does this refer to, and what is the role of grandparent stock in the larger picture of industrial poultry production?
In this detailed guide, we’ll explore the definition of grandparent stock, its origins on highly biosecure pedigree farms, its contribution to broiler production through the breeding pyramid, and why selecting quality grandparent stock is so crucial for the success and efficiency of the poultry industry Whether you’re a seasoned poultry farmer or simply curious about where your chicken dinner comes from, read on to learn more about this important foundation of the poultry supply chain
Defining Grandparent Stock
Grandparent stock, sometimes abbreviated as GP, refers to a specific generation or tier of pedigree breeding poultry Grandparent stock are the direct offspring of great-grandparent (GGP) breeding birds, and are used to produce parent stock (PS), which are then used for commercial meat production
So in essence, GGP birds produce GP birds, which then produce PS birds, which finally produce broilers and other commercial poultry. Grandparent stock sits one step removed from the apex of the breeding pyramid, but their genetics and productivity still directly impact the quality and efficiency of commercial chicken production.
Grandparent birds themselves are not used for meat production. Rather, they are bred and selected specifically for their genetic potential, and for their ability to pass desirable traits on to their PS offspring. Common traits selected for include feed conversion efficiency, growth rate, meat yield, and disease resistance.
Origins of Grandparent Stock
Grandparent flocks are housed on highly specialized pedigree farms, which operate at the top of the poultry breeding pyramid. These farms are characterized by stringent biosecurity measures, climate controlled housing, limited and controlled personnel access, and routine health monitoring. Such precautions are necessary to prevent disease and maintain the genetic integrity of the valuable grandparent breeding lines.
These elite pedigree lines can trace their origins back to breeders like Aviagen, Cobb-Vantress and Hubbard. Through decades of selection, these primary breeders have developed proprietary grandparent genetics designed for efficient commercial production. Grandparent chicks and hatching eggs are then supplied to customers around the world through contractual relationships.
Once received, the grandparent stock are raised in isolation to maturity. At around 25-30 weeks of age, they reach sexual maturity and begin producing fertilized hatching eggs. These eggs are then incubated by franchise hatcheries to produce the vital parent stock.
The Role of Grandparent Stock in Poultry Breeding
As described above, grandparent stock occupies a critically important generational link in the poultry breeding pyramid. By producing reliable quantities of high quality hatching eggs, the grandparent flocks supply the parent stock that enables commercial meat production on a massive scale. Without healthy, productive grandparent breeding, the entire system would falter.
Specifically, grandparent stock consists of male and female lines, both of which are hybrid crosses themselves. The male line is bred from mixes of breeds like Cornish, White Plymouth Rocks, and White Rocks. The female line typically contains White Plymouth Rock, White Leghorn, and White Cornish genetics.
These male and female grandparent lines are kept separate on pedigree farms. Their hatching eggs are then sent to customer parent stock farms and hatcheries. By crossing the male and female parent stock day-old chicks, the hybrid vigor and desired traits of the grandparent genetics are passed down to the commercial broiler chicken.
Importance of Quality Grandparent Stock
Because grandparent stock sits near the top of the breeding pyramid, its quality and health has cascading effects on all downstream production. Every trait of the grandparent stock – from disease resistance to growth rate to meat yield – will influence the performance of its parent stock offspring.
Therefore, primary breeders invest heavily in selecting only the very best grandparent breeding candidates. For example, Aviagen collects upwards of 200,000 data points on potential grandparent breeding lines before advancing them. Extensive testing and genetic analysis ensures that each successive generation excels in metrics like FCR, livability, and meat quality.
In addition, maintaining rigorous biosecurity on grandparent farms is equally crucial. An outbreak of disease at the GP level could be disastrous, resulting in mass culling and major supply disruptions downstream. For this reason, grandparent farms adhere to strict protocols covering everything from daily cleanings to personnel training to mandatory downtime between flocks.
By starting with healthy high performing grandparent stock, and propagating those genetics through the breeding pyramid, the poultry industry can meet the ever growing demand for affordable chicken meat. In short, without the care taken at the grandparent level, the astonishing efficiency of modern poultry production would not be possible.
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Cobb, Philippe Gouault – Grandparent Specialist
FAQ
What is the difference between grandparent stock and parent stock?
What is parent stock chicken?
How old are chickens when they are slaughtered?
What is the difference between a broiler chicken and a breeder chicken?
What is grandparent stock?
Grandparent stock refers to a specific generation of breeding birds in the poultry industry, which are used to produce the next generation of breeding birds. They are the offspring of great grandparent (GGP) stock and are kept on high level biosecure farms around the world.
Why is grandparent stock important in poultry production?
Grandparent stock plays a crucial role in the production of poultry for human consumption. The GP birds are carefully selected for their genetic traits, such as growth rate, feed conversion efficiency, and disease resistance. These traits are then passed down to the PS generation through the fertile eggs produced by the GP birds.
What is a parent stock hen?
Parent stock are then used in broiler breeder farms to produce fertilized eggs; their lineage will follow the diagram above with GGP hens producing broiler breeders, which in turn produce our Sunday roast. Males and females from parent stock are selected from different genetic lines or breeds and their chicks are hybrids.
What percentage of poultry is made up of GP stock?
Roughly 3% of the global population of poultry is made up from PS, GP and GGP stock, known collectively as Parent Stock. The US supplies around 25% of world GP stock. This is known as the primary breeding sector, and 417 million PS are produced every year. (Aviagen, 2011)