Breeding The Day-Old Meat Chicken
This web page covers aspects relating to the breeding of the day-old meat chicken. The following areas are covered:
Importing breeding birds and quarantine
Farm Biosecurity and Hygiene
Today’s meat chicken looks quite different from its wild ancestor - and quite different from modern laying chickens, which are bred specifically for egg production.
Rooster and hen of a modern meat breeder strain
Most commercial meat chickens that are raised for human consumption worldwide, originated from ‘great grand parent’ eggs from a handful of companies based in the US and the UK that specialise in selective breeding meat chickens. For them, the conducting of selective breeding programs and the developing breeding lines is highly specialised and resource intensive. Therefore, in the Australian industry, imported breeding stock gives access to the world’s best poultry genes.
Specialist breeding companies continuously improve their breeding lines to select for a large range of positive and healthy traits. For example, growth/meat yield and the efficiency with which birds convert feed to meat are critical, but breeders also look for egg production, fertility traits and resistance to disease and metabolic conditions
Importing breeding birds and quarantine
New genetic strains are imported as fertile eggs. These eggs have come from flocks which are monitored and rigorously tested before and after egg collection to ensure they are disease free. The eggs are sanitised on the outside and airfreighted to Australia in sealed containers. They are then transported directly to a quarantine facility – either a privately owned facility, or the government’s quarantine facility at Torrens Island. Quarantine aims to ensure exotic diseases do not enter Australia.
Quarantine facilities for hatching imported fertile eggs are highly biosecure premises designed to stop infection from escaping. For example, the air leaving the facility is filtered, strict protocols are followed to ensure that undesirable material cannot leave the facility on people, clothing, footwear, vehicles or equipment. Quarantine facilities are situated away from other poultry facilities to protect quarantined birds from common diseases.
Imported eggs are incubated and hatched in a local facility and the chickens are reared until their release at nine weeks. They are monitored and tested to confirm that they are free from a range of diseases common to poultry. These chickens are the great grand parents of chicken sold for Australian consumer consumption.
Great Grandparent Flocks
Birds released from quarantine (see Quarantine Facility) become the great grandparents of the chicken you purchase at your local shop or butcher (formally called a commercial broiler chicken).
Each importation may have three or four separate genetic lines – two female lines, with superior egg producing characteristics to ensure enough progeny can be produced, and one or two male lines, with superior traits to allow broilers to grow and convert feed at optimal rates.
Great grandparent breeders are reared on great grandparent breeder farms where they mature and produce fertile eggs which hatch to become the next generation, while maintaining purebred lines. Great grandparent hens start producing eggs from about 22 – 24 weeks and produce around 100 fertile eggs in their 52 week lifetime. For a description of their housing and management after leaving the quarantine facility (see Breeder Farm).
At any one time, there might be 20,000 to 24,000 great grandparents on the ground across the whole chicken meat industry in Australia. These are extremely valuable birds.
Fertile eggs from Great Grandparent flocks are hatched at a company hatchery (see Hatchery) to produce the Grandparents (GPs) of the commercial broiler chicken. These Grandparent flocks are reared and go on to produce fertile eggs on breeder farms similar to those used to house Great Grandparent flocks. There is some crossing of breeding lines in this generation, such that the resulting progeny will be of one of two distinct female and male lines.
Grandparent flocks start producing eggs at about 22-24 weeks of age and in their lifetime (to about 60 weeks of age) produce between 100 - 120 fertile eggs. At any one time, there might be between 200,000 to 250,000 Grandparents of all ages on the ground across Australia. These Grandparent flocks produce the next generation of birds, called the Parent breeders.
Parent breeders are hatched from the fertile eggs from grandparent flocks and, after arrival from the hatchery at one day-old, are reared, housed and managed similarly to great grandparent and grandparent flocks. Distinct male and female lines of parents are crossed to produce the next generation.
Parent birds are kept until approximately 64 weeks, and produce about 160 fertile eggs. There might be between 5.5 and 6 million parent birds at any given time across Australia. This third generation of breeders (the parents) produces chicken flocks whose meat is processed for human consumption (the commercial broiler chicken).
Surplus male breeders, and birds of breeding lines not needed for the next generation (referred to as ‘off-sexes’), are either culled upon hatching or grown out for meat.
Breeder flocks are kept in sheds on floors called litter floors (for example, covered with fresh, clean wood shavings or rice-hulls). Australian meat chickens are raised in sheds not cages.
The major poultry producing companies own breeding farms, in some cases supplemented by contract operators. Each breeding farm has a manager who works closely with company support staff, such as the livestock manager and veterinarian.
Breeder Flock Management During Rearing and Lay
On arrival at the breeder farm from the hatchery, day-old breeder chicks are placed on the floor of a climate controlled, well ventilated rearing shed with ready access to feed and water (see Rearing the Chickens).
As breeder flocks approach sexual maturity (18-20 weeks), they are transferred to laying sheds, which are similar to rearing sheds but include banks of elevated nest boxes. Most sheds provide one nest for every five hens. Usually the sheds have one male to every ten breeder hens.
While most breeder flocks are housed on deep litter during lay, some are housed on wooden slatted floors.
Breeding farms follow management programs recommended by the breeding company. Each new strain of bird has subtly different requirements, and fine-tuning requires a great deal of skill and experience. This may include managing bird health, maintaining the correct composition and quantity of feed, and ensuring proper lighting, with the aims of ensuring that:
birds remain healthy and productive
birds come into production at the right time
birds produce the optimal number of eggs over their laying cycle
birds produce fertile, high quality, hatchable eggs.
Breeder flocks are vaccinated against a range of diseases (see Keeping Flocks Healthy). This protects their own health and productivity and gives added protection to chicks through antibodies passed on in the yolk sac.
Feeding Breeder Flocks
Body weight and flock health is regularly monitored and reviewed. Breeder flock feed is usually restricted during rearing and lay to ensure the birds grow uniformly, as egg production can be affected by excess body fat. The composition of the feed for breeder flocks in lay differs from that given to broiler chickens (see Feed) in several key respects:
Breeder feed is lower in protein to satisfy the requirements for egg production vs growth.
Breeder feed is lower in energy content, to help slow growth rate/body weight.
Breeder feed is much higher in calcium to meet the hen’s needs for egg shell formation.
Breeder feed contains higher levels of key vitamins and trace minerals, which impact on the hatchability of their eggs.
Breeder chickens are not fed or in any way administered hormones in Australia.
Farm Biosecurity and Hygiene
One of the key elements of successful breeder farm management is maintaining good farm biosecurity. Biosecurity procedures aim to keep birds healthy by reducing the chance of disease getting onto the farm, spreading between sheds, or being passed between batches within the same shed.
Biosecurity measures on breeding farms include:
shower-on, shower-off (including washing hair) for all personnel and visitors
a complete change of clothes in the shower facility
strict control of visitor movements
wild animal-proof security fencing
locked security gates
bird, vermin and animal proofed sheds
treated water supply
full cleanout and decontamination of sheds between batches
restrictions placed on entry of feed and other vehicles to the property
full sanitation and fumigation of any equipment entering the farm
no staff or visitors to the farm to have had any contact with other poultry for 72 hours
footwear changed between sheds;
hands washed or gloves changed between sheds
When a breeder flock is removed from a shed, the shed and all equipment in it is rigorously cleaned and disinfected. The shed is then left empty for about three weeks before a new flock is placed to ensure that it is clean and ready for the next flock.
Eggs from breeder farms are sent to a hatchery for 21 days incubation.
Incubation can be delayed for up to a week, allowing hatching to be planned to meet the company’s future day-old chick needs. Eggs are fumigated at the hatchery, if this has not been done on the breeder farm, prior to entering the incubation process.
The hatching operation involves two stages, (1) the setter stage and (2) the hatcher stage. When the eggs are first received from breeding farms, they are placed in racks on shelves, fumigated and incubated in a machine called the setter for 18 days. These machines mimic the natural conditions a hen would provide for proper embryonic development, controlling temperature and humidity and turning the eggs hourly.
Eggs are transferred to the hatcher after 18 days and placed loose in trays . The hatcher provides similar conditions to the setter, but a slightly higher temperature, encouraging development and stimulating hatching. The second hatching stage takes three days.
Hatchability is the percentage of live chicks hatched. This is affected by:
The health, age, nutrition and fertility of the breeder flock – hatchability declines as flocks age.
The genetic line of breeder - eggs from Great Grandparent flocks might average up to 80% hatchability, rising to 85% hatchability for eggs from Parent flocks.
How well incubation conditions have met the embryo’s needs
How well eggs have been handled since being laid
When a chick hatches it takes what remains of the yolk inside its abdomen, giving it nutrients which last until it is delivered to a farm where it will be reared.
Good hatchery hygiene is important to ensure that the chicks do not pick up an infection in the hatchery and are healthy and vigorous on release. After hatching, chicks are graded and in some cases divided by sex. They may be vaccinated for diseases such as infectious bronchitis, Newcastle disease and Marek’s disease. The chicks are then counted and dispatched to breeding or broiler-growing farms.