Chickens reared for meat are called broilers or broiler chickens. They originate from the jungle fowl of the Indian Subcontinent. The broiler industry has grown due to consumer demand for affordable poultry meat.
Breeding for particular traits and improved nutrition have been used to increase the weight of the breast - muscle.
Commercial broiler chickens are bred to be very fast growing in order to gain weight quickly.
In their natural environment, hens spend much of their time foraging for food. This means that they are highly motivated to perform species specific behaviours that are typical for chickens (natural behaviours),such as foraging, pecking, scratching
and feather maintenance behaviours like preening and dust-bathing.
Trees are used for perching at night to avoid predators.
The life of chickens destined for meat production consists of two distinct phases. They are born in a hatchery and moved to a growing farm at 1 day-old.
They remain here until they are heavy enough to be slaughtered. This document gives an overview of a typical broiler’s life.
The hatchery
The parent birds (breeder birds-see also section at end) used to produce meat chickens have their eggs taken away and placed in an incubator. In here, the eggs are kept in an optimum constant atmosphere and regulated temperature.
At 21 days, the chicks are ready to hatch, using their egg tooth to break out of their shell (in a natural situation, the mother would help with this). Chicks are precocial
, meaning that immediately after hatching they are relatively mature and can walk around. A chick classified as a ‘day-old chick’ is up to 72 hours old (this is when the
yolk sac in the egg runs out).
At present, chicks destined for organic systems are not treated differently until they get to the growing farm.
Chicks need extra heat and high humidity during the first weeks of life. Newly hatched chicks require ambient temperatures of 32°C to 35°C and relative humidity
of 60% to 70% which can be difficult to achieve at these high temperatures.
Vaccination
The modern broiler reaches slaughter weight within several weeks. This leaves little time to develop a mature immune system.
Therefore, broiler chicks (including organic chicks) are vaccinated against several
different diseases.
Some infectious pathogens (such as Salmonella) can also be transmitted via the egg (vertical transmission) from the breeder hen to the chick. The breeder hen
should therefore also be vaccinated.
The most common vaccines used are against Newcastle disease virus, infectious bronchitis virus, avian pneumovirus, infectious bursal disease and Marek’s disease (organic systems do not currently vaccinate against Marek’s disease due to the necessity to use an antibiotic on the skin after administration).
Vaccines are delivered via spraying or via drinking water. Spray vaccination is the preferred and most effective administration technique for respiratory type vaccines.
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