Backyard Poultry Basics

Housing

The enclosure that a backyard poultry flock will occupy must take into account the basic need for an outdoor pen as well as secure housing - the coop - for nighttime security. The overall design is limited only by the imagination of the builder.

The square footage of the habitat is dictated by the number of birds and their age. Obviously, the greater the number of birds and the older they are, the larger the minimum square footage. General guidelines suggest roughly 100 in² for birds under 6 weeks of age, twice that (200 in²) for 6- to 18-week-old birds, and twice that (400 in²) for those over 18 weeks.

The actual flooring of the coop is not critical since it will be covered with substrate. It may consist of plywood, particle board, concrete, etc., but management techniques may influence its selection. For example, particle board would not hold up to being hosed down during a semiannual cleaning. The substrate may consist of any absorbent, low dust-producing material that dries quickly and does not facilitate the growth of mold. Wood shavings (from other than hardwoods), shredded paper, sand, even recycled paper litter for cats are all acceptable. It is actually not necessary to replace the bedding more than twice per year, provided it is kept dry. Water from a leaky roof, etc., poses a serious threat to the health of the flock by facilitating the growth of mold and fungus, which could translate into serious respiratory disease in the flock. As long as the litter remains dry, only spot cleaning and occasional supplementation of the bedding are necessary.

Temperature and Humidity

A commonly overlooked aspect of the coop is ventilation. Ample air flow through the coop is essential for the reduction of humidity, the elimination of gases (e.g., ammonia) produced by the decomposition of droppings in the bedding, the avoidance of overheating, etc. Winter presents a challenge in the sense that the coop must provide warmth, but not at the expense of ventilation. The design of the coop must allow for some degree of air exchange throughout the year, with the reduction of humidity within the coop being the primary objective. A temperature inside the coop of 50–75° is considered ideal, with the humidity being as low as possible.

Lighting

As long as the flock is exposed to natural daylight, ambient lighting throughout North America is typically adequate for normal growth and development of chickens. A hanging bulb may be beneficial for providing warmth to hatchlings, but its value is solely for the heat it produces - the additional lighting it provides is not relevant to the chicks' development. More important than the intensity of the lighting is the duration. Increasing the photoperiod increases both egg production and growth for meat production, but a maximum of 16 hours per day, achieved gradually, is considered optimal. It should be recognized that egg production will decrease or even cease if the photoperiod is subsequently shortened, so continued production can be facilitated by providing artificial lighting.

Nutrition

With commercial diets readily available, nutrition should rarely be a problem for backyard poultry flocks. Still, problems related to improper mixing and extended storage can lead to both deficiencies and contamination. Additionally, water is a "nutrient" that must be given serious consideration. Problems relating to water supply are probably more common than those relating to the actual diet.

Different stages of growth and different purposes for the chickens each demand specific diets. For example, layers perform best on diets designed for laying, while broilers and show birds may actually experience complications on such diets. Gout is a common problem arising in broilers being fed a layer diet.

Deficiencies arise for two main reasons. First, owners will occasionally attempt to lower the cost of feed by diluting a formulated diet with scratch, such as cracked corn. This significantly compromises the quality of the formulated diet, resulting in an excess of some nutrients, such as carbohydrates, and a deficiency of vitamins and minerals. The second reason for deficiencies is extended storage times. Many vitamins decay over time, and vitamin concentrations may effectively be lowered the longer the food is stored. High storage temperatures exacerbate this phenomenon.

The simplest way to ensure ideal nutrition is to offer life-stage specific commercial diets in pure form, without adding additional components of any kind.

Viral Disease

Avian influenza is a catch-all name for an Orthomyxoviridae of which there are 144 different serotypes. The most familiar is H5N1, the agent responsible for epidemics around the world, including approximately 400 human deaths and a mortality rate in people of 60%. The H5N1 virus was not detected in the U.S. until January 2015, but its virulence is not as severe as the Asian strain. Swine flu is another familiar strain of avian influenza caused by the H1N1 strain. Because the AI virus is carried primarily by waterfowl, chickens having exposure to migratory ducks and geese experience the greatest risk of exposure, yet the risk of disease is minimal. Clinical signs of avian influenza are related to the particular strain and its individual pathogenicity. Signs, if any, may range from minimal lethargy and respiratory disease, to rapid deterioration with CNS signs and death. Probably the greatest significance of AI is that it is clinically indistinguishable from Newcastle disease, which, if introduced into the U.S., could destroy a substantial portion of the poultry industry.

Perhaps the greatest threat to the U.S. poultry industry is exotic viscerotrophic velogenic Newcastle disease, or paramyxovirus type 1 (PMV-1). Its occurrence in the U.S. is extraordinarily rare, and outbreaks are often associated with exposure to smuggled pet birds. When such outbreaks occur, the course of action is aggressive depopulation. Clinical signs begin with respiratory signs such as sneezing and coughing, and rapidly progress to neurologic signs including torticollis, stargazing, and paralysis. Cases demonstrating these symptoms should immediately be reported to local agricultural agents.

Marek's disease is probably the virus most likely to cause problems in backyard poultry flocks. While easily prevented by obtaining only vaccinated chicks, the nature of backyard poultry farming and the likelihood of introducing individuals from random sources make the disease more common than most of the other viruses. Caused by a herpesvirus, clinical signs usually appear as neurologic presentations or tumors throughout the viscera or skin. Diagnosis is obtained principally through histopathology. Because this disease is quite preventable, clients should be encouraged to purchase only vaccinated chicks and only from reputable sources.

Infectious laryngotracheitis is another disease caused by a herpesvirus. As the name suggests, clinical signs include a severe, occlusive tracheitis with blood-tinged exudate and high mortality. While serious in the individuals it affects, the incidence in backyard flocks is relatively low.

Lymphoid leucosis, caused by an oncovirus, is another disease manifested by the appearance of lymphoid tumors throughout infected individuals. The hallmark of this disease is its tendency to only affect birds greater than 14 weeks of age, and lesions are almost always found primarily in the bursa of Fabricius. Historically, the incidence of the disease may be enhanced through vaccination for Marek's disease, although most commercial poultry flocks have evolved a large degree of resistance to the virus.

Infectious bronchitis, caused by an avian coronavirus, is probably the most common viral respiratory disease of domestic poultry. The disease is highly contagious, with an incubation period of as little as 18 hours, and it causes typical, nonspecific respiratory signs (e.g., sneezing, coughing, head-shaking, etc.). In uncomplicated cases, the mortality rate may be low, but secondary infections can lead to mortality of up to 25%. Diagnosis is usually achieved through serology.

Fowl pox, caused by, obviously, a pox virus, may appear in two forms: cutaneous and diphtheritic. The cutaneous form is characterized by granulomatous progressing to caseous lesions on unfeathered parts of the body such as the eyelids or oral commissures. The virus does not easily penetrate intact epithelium, and perforation of the skin from mosquitos, biting flies, fighting, etc. facilitates infection. The diphtheritic form appears as severe mucosal inflammation and pseudomembrane formation in the oropharynx and upper airways. Mortality in diphtheritic cases is high and rapid, while that of cutaneous cases depends on the severity of the infection.

Infectious bursal disease, or Gumboro disease, is caused by a birnavirus. This disease is an acute, highly contagious infection in chickens, manifested by inflammation and atrophy of the bursa of Fabricius. Chickens between the ages of 3–6 weeks are most affected, since this is the period of maximal bursal activity. Morbidity may be extremely high, up to 100%, but mortality is usually low.

Egg drop syndrome, caused by an adenovirus, is a disease in layer hens manifested by a sudden drop in egg production, failure to reach peak production, irregularly shaped eggs, soft-shelled or shell-less eggs and depigmentation of the eggs. Aside from inflammation in the ovary and oviduct, no other lesions occur.