Poultry are domesticated birds kept by humans for the purpose of harvesting useful animal products such as meat, eggs or feathers, and the practice of raising poultry is known as poultry farming. These birds are most typically members of the superorder Galloanserae (fowl), especially the order Galliformes. The term also includes waterfowls of the family Anatidae and other flying birds that are kept and killed for their meat such as the young pigeons, but does not include wild birds hunted for food known as game or quarry.
Debeaking, beak trimming, or beak conditioning is the partial removal of the beak of poultry, especially layer hens and turkeys although it may also be performed on quail and ducks. Most commonly, the beak is shortened permanently, although regrowth can occur. The trimmed lower beak is somewhat longer than the upper beak. A similar but separate practice, usually performed by an avian veterinarian or an experienced birdkeeper, involves clipping, filing or sanding the beaks of captive birds for health purposes – in order to correct or temporarily to alleviate overgrowths or deformities and better allow the bird to go about its normal feeding and preening activities. Amongst raptor-keepers, this practice is commonly known as "coping".
The domestic turkey is a large fowl, one of the two species in the genus Meleagris and the same species as the wild turkey. Although turkey domestication was thought to have occurred in central Mesoamerica at least 2,000 years ago, recent research suggests a possible second domestication event in the area that is now the southwestern United States between 200 BC and AD 500. However, all of the main domestic turkey varieties today descend from the turkey raised in central Mexico that was subsequently imported into Europe by the Spanish in the 16th century.
Breed broiler is any chicken that is bred and raised specifically for meat production. Most commercial broilers reach slaughter weight between four and six weeks of age, although slower growing breeds reach slaughter weight at approximately 14 weeks of age. Typical broilers have white feathers and yellowish skin. Broiler or sometimes broiler-fryer is also used sometimes to refer specifically to younger chickens under 2.0 kilograms, as compared with the larger roasters.
Free range denotes a method of farming husbandry where the animals, for at least part of the day, can roam freely outdoors, rather than being confined in an enclosure for 24 hours each day. On many farms, the outdoors ranging area is fenced, thereby technically making this an enclosure, however, free range systems usually offer the opportunity for the extensive locomotion and sunlight that is otherwise prevented by indoor housing systems. Free range may apply to meat, eggs or dairy farming.
Battery cages are a housing system used for various animal production methods, but primarily for egg-laying hens. The name arises from the arrangement of rows and columns of identical cages connected, in a unit, as in an artillery battery. Although the term is usually applied to poultry farming, similar cage systems are used for other animals. Battery cages have generated controversy between advocates for animal welfare and industrial producers.
Poultry farming is the form of animal husbandry which raises domesticated birds such as chickens, ducks, turkeys and geese to produce meat or eggs for food. Poultry – mostly chickens – are farmed in great numbers. More than 60 billion chickens are killed for consumption annually. Chickens raised for eggs are known as layers, while chickens raised for meat are called broilers.
Dust bathing is an animal behavior characterized by rolling or moving around in dust, dry earth or sand, with the likely purpose of removing parasites from fur, feathers or skin. Dust bathing is a maintenance behavior performed by a wide range of mammalian and avian species. For some animals, dust baths are necessary to maintain healthy feathers, skin, or fur, similar to bathing in water or wallowing in mud. In some mammals, dust bathing may be a way of transmitting chemical signals to the ground which marks an individual's territory.
Abnormal behavior of birds in captivity has been found to occur among both domesticated and wild birds. Abnormal behavior can be defined in several ways. Statistically, 'abnormal' is when the occurrence, frequency or intensity of a behaviour varies statistically significantly, either more or less, from the normal value. This means that theoretically, almost any behaviour could become 'abnormal' in an individual. Less formally, 'abnormal' includes any activity judged to be outside the normal behaviour pattern for captive birds of that particular class or age. For example, running rather than flying may be a normal behaviour and regularly observed in one species, however, in another species it might be normal but becomes 'abnormal' if it reaches a high frequency, or in another species it is rarely observed and any incidence is considered 'abnormal'. This article does not include 'one-off' behaviours performed by individual birds that might be considered abnormal for that individual, unless these are performed repeatedly by other individuals in the species and are recognised as part of the ethogram of that species.
Sham dustbathing is a behaviour performed by some birds when kept in cages with little or no access to litter, during which the birds perform all the elements of normal dustbathing, but in the complete absence of any substrate. This behaviour often has all the activities and temporal patterns of normal dustbathing, i.e. the bird initially scratches and bill-rakes at the ground, then erects its feathers and squats. Once lying down, the behaviour contains four main elements: vertical wing-shaking, head rubbing, bill-raking and scratching with one leg. Normal dustbathing is a maintenance behaviour whose performance results in dust collecting between the feathers. The dust is then subsequently shaken off which reduces the amount of feather lipids and so helps the plumage maintain good insulating capacity and may help control of ectoparasites.
Vent pecking is an abnormal behaviour of birds performed primarily by commercial egg-laying hens. It is characterised by pecking damage to the cloaca, the surrounding skin and underlying tissue. Vent pecking frequently occurs immediately after an egg has been laid when the cloaca often remains partly everted exposing the mucosa, red from the physical trauma of oviposition or bleeding if the tissue is torn by her laying an egg. Vent pecking clearly causes pain and distress to the bird being pecked. Tearing of the skin increases susceptibility to disease and may lead to cannibalism, with possible evisceration of the pecked bird and ultimately, death.
Toe pecking, an abnormal behaviour of birds in captivity, occurs when one bird pecks the toes of another using its beak. This behaviour has been reported in hens and ostriches. Studies have shown that hens exposed to toe pecking have significantly enlarged adrenal glands, indicating increased physiological stress. Hens exposed to toe pecking will step off a raised platform more quickly than control hens, possibly suggesting a heightened fear of elevation. They have also been reported to show depressive behaviour when afflicted by toe-pecking. The act of toe pecking leads to open wounds which are viable for infection and disease to develop. In severe forms, toe pecking can be classified as a cannibalistic behaviour and has been reported as a cause of mortality.
Animal welfare science is the scientific study of the welfare of animals as pets, in zoos, laboratories, on farms and in the wild. Although animal welfare has been of great concern for many thousands of years in religion and culture, the investigation of animal welfare using rigorous scientific methods is a relatively recent development. The world's first Professor of Animal Welfare Science, Donald Broom, was appointed by Cambridge University (UK) in 1986.
Cannibalism in poultry is the act of one individual of a poultry species consuming all or part of another individual of the same species as food. It commonly occurs in flocks of domestic hens reared for egg production, although it can also occur in domestic turkeys, pheasants and other poultry species. Poultry create a social order of dominance known as pecking order. When pressure occurs within the flock, pecking can increase in aggression and escalate to cannibalism. Cannibalism can occur as a consequence of feather pecking which has caused denuded areas and bleeding on a bird's skin. Cannibalism can cause large mortality rates within the flock and large decreases in production due to the stress it causes. Vent pecking, sometimes called 'cloacal cannibalism', is considered to be a separate form of cannibalistic pecking as this occurs in well-feathered birds and only the cloaca is targeted. There are several causes that can lead to cannibalism such as: light and overheating, crowd size, nutrition, injury/death, genetics and learned behaviour. Research has been conducted to attempt to understand why poultry engage in this behaviour, as it is not totally understood. There are known methods of control to reduce cannibalism such as crowd size control, beak trimming, light manipulation, perches, selective genetics and eyewear.
A furnished cage, sometimes called enriched cage, colony cage or modified cage, is a type of cage used in poultry farming for egg laying hens. Furnished cages have been designed to overcome some of the welfare concerns of battery cages whilst retaining their economic and husbandry advantages, and also provide some of the welfare advantages over non-cage systems. Many design features of furnished cages have been incorporated because research in animal welfare science has shown them to be of benefit to the hens.
Chicken eyeglasses, also known as chicken specs, chicken goggles, generically as pick guards, and under other names, were small eyeglasses made for chickens intended to prevent feather pecking and cannibalism. They differ from blinders in that they allow the bird to see forward, whereas blinders do not. One variety used rose-colored lenses, as the coloring was thought to prevent a chicken wearing them from recognizing blood on other chickens, which may increase the tendency for abnormal injurious behavior. They were mass-produced and sold throughout the United States as early as the beginning of the 20th century.
Dubbing is the procedure of removing the comb, wattles and sometimes earlobes of poultry. Removing the wattles is sometimes called "dewattling".
Blinders, also known as peepers, are devices fitted to, or through, the beaks of poultry to block their forward vision and assist in the control of feather pecking, cannibalism and sometimes egg-eating. A patent for the devices was filed as early as 1935. They are used primarily for game birds, pheasant and quail, but also for turkeys and laying hens. Blinders are opaque and prevent forward vision, unlike similar devices called spectacles which have transparent lenses. Blinders work by reducing the accuracy of pecking at the feathers or body of another bird, rather than spectacles which have coloured lenses and allow the bird to see forwards but alter the perceived colour, particularly of blood. Blinders are held in position with a circlip arrangement or lugs into the nares of the bird, or a pin which pierces through the nasal septum. They can be made of metal (aluminium), neoprene or plastic, and are often brightly coloured making it easy to identify birds which have lost the device. Some versions have a hole in the centre of each of the blinders, thereby allowing restricted forward vision.
Christine Nicol is an author, academic and a researcher. She is a Professor of Animal Welfare at the Royal Veterinary College and has honorary appointments at the University of Oxford and the University of Lincoln. She is the Field Chief Editor of Frontiers in Animal Science.
