Poultry birds that have been domesticated to reproduce and grow in captivity and that render products of economic value such as meat, eggs, feathers, fertiliser, animal food, and pharmaceuticals. Chickens, ducks, muscovies, geese, Guinea fowl, quail, pigeon, pheasants, and turkeys are generally considered as poultry birds.

The domestic chicken, Gallus domesticus likely had its ancestry in the red jungle fowl, Gallus gallus that originated in Southeast Asia. It appears that people probably domesticated chicken over 4,000 years ago, after centuries of hunting the wild jungle fowl for food. In ancient India these chickens were also used in religious ceremonies dedicated to the Sun god. Chickens then probably spread through eastern Asia and reached Persia about 1000 BC and played role in their ancient religion.

Domesticated Guinea fowl derived from the helmeted Guinea fowl (Numida meleagris) of Africa. It is reported that early domestication had occurred in two areas- in southern Sudan and in West Africa but the dates are not certain. Guineas were well known to the Greeks and Romans in classical times. However, nearly all modern Guinea fowls are likely to have been derived from Portuguese introduction of the West African subspecies N. m. galeata. It is found that Guineas appear to have been domesticated for almost as long as chickens.

It has been accepted since antiquity that domestic ducks were derived from the wild mallard (Anas platyrhynchos). Wild and domestic forms differ in only very minor ways, they interbreed freely and the hybrids are fully fertile. Domestic turkeys had been derived from a Mexican subspecies. Place and date of domestication are not known with any certainty.

The local variety of chickens being less productive in respect of meat and egg production, there has been tendency to establish poultry farms, small or large, having improved varieties of poultry birds. These include breeds like White Leghorn, Rhode Island Red, Plymouth Rock, Assel, Winedot etc. Compared to local forms these birds are larger and may gain a weight upto 4 kg. The White Leghorn is more popular in Bangladesh and the female birds may lay nearly 230 eggs per year. The quail (Coturnix coromandelica and Turnix tanki) is also gaining popularity in Bangladesh. This small bird, having a weight of about 150 g, may lay over 200 eggs annually.

The total number of fowl and duck in Bangladesh was about 188.3 million during 2005. The estimated current production of eggs by the poultry is about 536.9 million. [Shafiuddin Ahmed]

Poultry diseases Avian tuberculosis a bacterial disease of the poultry birds caused by Mycobacterium tuberculosis. The disease has a wide distribution, but is particularly prevalent in general farms and in household birds kept in many years. Fowls, turkeys, and Guinea fowls are readily affected, but geese and ducks are less commonly infected. Infection occurs following ingestion of food and water contaminated by the droppings of affected birds. Lameness is sometimes noticed together with the loss of weight.

Coccidiosis caused by an obligate intracellular protozoa of the genus Eimeria, is a major economically important protozoan disease. Seven species of Eimeria occur in poultry of which E. tenella is most pathogenic and causes caecal coccidiosis, often with high mortality. The birds droop, cease feeding, and blood appears in the faeces 3-4 days after infection.

Fowl cholera an infectious disease of fowl caused by the bacterium Pasteurella sp. It is also known as chicken cholera and haemorrhagic septicemia of fowl. In Bangladesh the disease often appears in epidemic form. Fowls of 3-6 months old are more susceptible. The infection is transmitted by contaminated soil, food and water.

Fowl paralysis a viral disease of poultry, found almost all countries of the world. In Bangladesh fowl paralysis affects birds most commonly between the ages of three and eight months. Local varieties are less susceptible. Affected birds may show lameness of one or both legs. This lameness becomes progressively worse, and general paralysis results.

Fowl pox a viral disease of chicken in which wart-like nodules, varying in size from that of a pea to little larger than that, appear on the comb, eyelids, and openings of the nostrils and ears, or on other parts of the head. In Bangladesh the disease is usually prevalent in winter.

Fowl typhoid a septicemic disease of domestic birds is caused by Bacillus (=Salmonella) gallinarum. The natural mode of infection is through food and water contaminated by faeces of diseased and carrier birds. The disease has a world-wide distribution and in Bangladesh it is more prevalent in summer. Chickens of all ages are susceptible. The mortality rate may range from 20-80%.

Gapes a disease of young chickens caused by a small round worm, Syngamous trachea. This worm lives in trachea, bronchi or bronchioles of poultry. The obstruction of trachea by worms and frothy mucus cause difficulty in breathing. The birds may gape and breathe with a hissing sound, cough and shake, or toss their heads and stretch out the neck. In Bangladesh gapes is fairly common in young poultry birds.

Gumboro disease an acute viral disease of poultry. In recent years heavy mortality of young chickens in poultry farms of Dhaka and its suburbs was thought to be due to Gumboro disease. About 70 percent chicks of 4 to 7 days old become victim of the disease. Death may exceed 50 percent. This infectious disease quickly may spread through contaminated food. Severe diarrhoea is the principal symptom together with untidy feathers.

Newcastle disease (Ranikhet) is another viral disease somewhat resembling fowl plague, but is caused by a separate and immunologically distinct virus. The disease is so named because it was first recorded near Newcastle in England in 1926. Newcastle disease is characterized by sneezing, coughing, and nervous behaviour. Affected birds may show tremors, circling, falling, and twisting of the head and neck or complete paralysis. Fowls of all ages are susceptible to this disease, but usually chickens of 3 to 8 weeks are more severely affected. Mortality may range from 80 to 100%. The principal symptom is yellowish white, lime-like evil-smelling diarrhoea. A long, gasping inhalation through the opened beak is also a characteristic symptom.

In rural Bangladesh this disease is quite prevalent and is the principal cause of fowl mortality. Among the affected laying hens, egg quantity and quality drop sharply. The disease can be controlled in poultry by sanitary management and isolation of flocks. Vaccines are now available for treatment. [Shafiuddin Ahmed and M Jahurul Karim]

Poultry parasites A number of important pests and parasites occur in poultry in Bangladesh, most of those, however, belong to Arthropoda and Platyhelminthes. Argas persicus, a soft tick lives in the cracks and crevices of the poultry house, visits the host at night, causes sleeplessness, anaemia and loss of productivity, and transmits fowl spirochaetosis and rickettsia.

The lice, which includes Goniodes dissimilis, Goniocotes gallinae, Lipeurus caponis, L. lawrensis, Menopon gallinae, Menacanthus stramineus, and M. pellidulus, prefer the skin surface as their habitat, causes irritation, loss of body weight, debility, depressed egg production and perhaps death in young birds.

Twelve helminths (Ascaridia galli, Heterakis gallinarum, Capillaria annulata, C. columbae, Acuaris spiralis, Amoebotaenia sphenoides, Hymenolepis carioca, Raillietina tetragona, R. echinobothrida, R. cesticillus, Echinostoma revolutum and Catatropis verrucosa) occur in poultry in Bangladesh of which A. galli and Raillietina spp. produce disease of economic importance. Raillietina echinobothrida is the most pathogenic of the three species, which produce nodules at the site of attachment. The parasite is very common in village poultry. [M Jahurul Karim]