Diploma in Nursing Admission Test Question Solution 2023.pdf
Breeding meat chickens
1. Breeding Meat Chickens
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.
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.
Breeder Flocks
Great Grandparent Flocks
Birds released from quarantine 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.
2. 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.
Grandparent Flocks
Fertile eggs from Great Grandparent flocks are hatched at a company 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 Flocks
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).
3. 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 Farms
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.
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
4. 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:
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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. 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 in several key respects:
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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.
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:
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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;
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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.
Hatchery
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
Hatchability is the percentage of live chicks hatched. This is affected by:
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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.
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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.
Hatchery
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
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.