A broiler Gallus gallus domesticus is any chicken that is bred and raised specifically for meat production. Most commercial broilers reach slaughter-weight between four  and seven weeks of age, although slower growing breeds reach slaughter-weight at approximately 14 weeks of age. Because the meat broilers are this young at slaughter roughly gtheir behaviour and physiology are that of an immature bird.
Due to extensive breeding selection for rapid early growth and the husbandry used to sustain this, broilers are susceptible to several welfare concerns, particularly skeletal malformation and dysfunction, skin and eye lesions, and congestive heart conditions. Management of ventilation, housing, stocking density and in-house procedures must be evaluated regularly to support good welfare of the flock.
The breeding stock broiler-breeders grow to maturity and beyond but also have welfare issues related to the frustration of a high feeding motivation and beak trimming. Broilers are usually grown as mixed-sex flocks in large sheds under intensive conditions. Before the development of modern commercial meat breeds, broilers were mostly young male chickens culled from farm flocks.
Pedigree breeding began around The original hybrid was plagued by problems of low fertility, slow growth and disease susceptibility. As an example, Donald Shaver originally a breeder of egg-production-breeds began gathering breeding stock for a broiler program in A white feathered female line was purchased from Cobb.
A full scale breeding program was commenced inwith commercial shipments in and the US in and in Europe in As a second example, colour sexing broilers was proposed by Shaver in The genetics were based on the company's breeding plan for egg-layers which had been developed in the mids. A difficulty facing the breeders of the colour-sexed broiler is that the chicken must be white-feathered by Breeding white women age.
After 12 years, accurate colour sexing without compromising economic traits was achieved. Artificial insemination is a mechanism in which Breeding white women are deposited into the reproductive tract of a female. Broiler breeds have been selected specifically for growth, causing them to develop large pectoral muscles, which interfere with and reduce natural mating.
Additionally, the males overall sex drive may be significantly reduced due to growth selection. Abdominal massage is the most common method used for semen collection. This is done gently but quickly. Within a short period of time, the male should get an erection of the phallus. Once this occurs, the cloaca is squeezed and semen Breeding white women collected from the external papilla of the vas deferens .
During artificial insemination, semen is most frequently deposited intra-vaginally
Breeding white women means of a plastic syringe. In order for semen to be deposited here, the vaginal orifice is everted through the cloaca. This is simply done by applying pressure to the abdomen of the hen. Modern commercial broilers, for example, Cornish crosses and Cornish-Rocks [ citation needed ]are artificially selected and bred for large-scale, efficient meat production. They are noted for having very fast growth rates, a high feed conversion ratioand low levels of activity.
Slow growing free-range and organic strains have been developed which reach slaughter-weight at 12 to 16 weeks of age. Typical broilers have white feathers and yellowish skin. Recent genetic analysis has revealed that the gene for yellow skin was incorporated into domestic birds through hybridization with the grey junglefowl G.
For example, the activity of broilers reared outdoors is initially greater than broilers reared indoors, but from six weeks of age, decreases to comparable levels in all groups. There is evidence of reduced motivation to extend the behavioural repertoire, as, for example, ground pecking remained at significantly higher levels in the outdoor groups because this behaviour could also be performed from a lying posture rather than standing.
Examining the frequency of all sexual behaviour shows a large decrease with age, suggestive of a decline in libido. The decline in libido is not enough to account Breeding white women reduced fertility in heavy cocks at 58 weeks and is probably a consequence of the large bulk or the conformation of the males at this age
Breeding white women in some way with the transfer of semen during copulations which otherwise look
Breeding white women.
Chickens are omnivores and modern broilers are given access to a special diet of high protein feed, usually delivered via an automated feeding system. This is combined with artificial lighting conditions to stimulate eating and growth and thus the desired body weight.
In the figure
Breeding white women 4. Canada has a typical FCR of 1. New Zealand commercial broiler farms have recorded the world's best broiler chicken FCR, consistently at 1. Artificial Breeding white women has led to a great increase in the speed with which broilers develop and reach slaughter-weight. The time required to reach 1. Selection for fast early growth-rate, and feeding and management procedures to support such growth, have led to various welfare problems in modern broiler strains.
Selection and husbandry for very fast growth means there is a genetically induced mismatch between the energy-supplying organs of the broiler and its energy-consuming organs.
SDS is an acute heart failure disease that affects mainly male fast-growing broilers which appear to be in good condition. Affected birds suddenly start to flap their wings, lose their balance, sometimes cry out and then fall on their backs or sides and die, usually all within a minute. InSDS has a death rate of 0.
Ascites is characterised by hypertrophy and dilatation Breeding white women the heart, changes in liver function, pulmonary insufficiency, hypoxaemia and accumulation of large amounts of fluid in the abdominal cavity.
Ascites develops gradually and the birds suffer for an extended period before they die. In the UK, up to 19 million broilers die in their sheds from heart failure each year.
Most broilers find walking painful, as indicated by studies using analgesic and anti-inflammatory drugs. In Breeding white women experiment, healthy birds took 11 seconds to negotiate an obstacle course, whereas lame birds took 34 seconds.
After the birds had been treated with carprofenthere was no effect on the speed of the healthy birds, however, the lame birds now took only 18 seconds to negotiate the course, indicating that the pain of lameness is relieved by the drug.
Several research groups have developed "gait scores" GS to objectively rank the walking ability and lameness of broilers. The video recordings below are examples of broilers attempting to walk with increasing levels of gait abnormalities and therefore increasing gait scores.
This increased inactivity is linked with an increase in dermatitis caused by a greater amount of time in contact with ammonia in the litter. This contact dermatitis is characterised by hyperkeratosis and necrosis of the epidermis at the affected sites; it can take forms such as hock burns, breast blisters and foot pad lesions. Broilers are usually kept at high stocking densities which vary considerably between countries.
The reduced growth rate is likely due to a reduced capacity to lose heat generated by metabolism. Higher stocking densities are associated with increased dermatitis including food pad lesions, breast blisters and soiled plumage. In attempts to improve or maintain fast growth, broilers are kept under a range of lighting conditions. These include continuous light fluorescent Breeding white women incandescentcontinuous darkness, or under dim light; chickens kept under these Breeding white women conditions develop eye abnormalities such as macrophthalmos, avian glaucomaocular enlargement and shallow anterior chambers.
The litter in broiler pens can become highly polluted from the nitrogenous feces of the birds and produce ammonia. Ammonia has been shown to cause increased susceptibility to disease and other health-related problems such as Newcastle diseaseairsaculitis and keratoconjunctivitis.
The respiratory epithelium in birds is damaged by ammonia concentrations
Breeding white women the air exceeding 75 parts per million ppm. Once the broilers have reached the target live-weight, they are caught, usually by hand, and packed live into crates for transport to the slaughterhouse.