This is a list of terms commonly used in the poultry industry. It is by no means all inclusive nor are the definitions claimed to be universally used. Minor variations in the way the terms are used may be found from region to region.
Addled: an egg where the contents are decomposing.
Air cell: the air space usually found at the large or blunt end of an egg.
Albumen: the white of an egg.
Amino acids: the simpler building units of protein.
Anticoccidial: an anticoccidial drug used to treat or prevent coccidiosis
Artificial insemination: the introduction of semen into the female oviduct by methods other than by natural mating.
Aviary system: a ‘litter system’ of housing where a number of “mezzanine” floors are installed to increase the available floor space and, in doing so, provide the space for more birds in the poultry house.
Beak trimming: The removal of the tip of the beak of poultry by specially designed equipment to prevent cannibalism and its associated vices.
Blastoderm: The fertilised nucleus of the egg from which the chicken develops.
Blastodisc: The unfertilised nucleus of an egg. No chicken can develop from a blastodisc.
Breed: A group of birds that reproduce their own likeness in their offspring. A variety is a group within a breed that are distinguished by a difference of a single characteristic eg. feather colour or comb type.
Broiler: A young bird of either sex that is bred and grown specifically for highly efficient meat production. Broilers are usually grown for 5 to 7 weeks of age (alternative term – meat chicken).
Brooder: The equipment used to provide supplementary warmth during the early stages of the chickens’ life. The energy used may come from electricity, gas, oil or from other sources.
Brooding: The period of the first weeks of a chicken’s life when it requires a very high standard of care including the provision of special diets and supplementary warmth.
Broody: The instinct controlled by maternal hormones that causes the female to want to sit on eggs for hatching and to care for the chickens that hatch.
Caeca: The two blind gut of the digestive tract attached to the distal end of the small intestine.
Cages: A system of housing where the birds are confined to a wire floor singly or in multiples. With this system the stock do not come into contact with their own or other bird’s faeces which is an important disease control measure.
Candle: To assess some internal characteristics of the egg by viewing it in a darkened room with a bright light behind the egg.
Cannibalism: The practice by some birds of attacking and eating other members of the same flock.
Chalazae: A type of albumen that surrounds the yolk of the egg and extends as creamy white, twisted, ropelike structures into each end to anchor the yolk in the centre of the egg.
Chick: The term used to describe chickens from day old to the end of brooding.
Chick-type drinker: A drinker that is more suitable for young chickens to access water.
Chick-type feeder: A feeder that is more suitable for young chickens to access food.
Clear eggs: Infertile eggs (containing no embryos) usually removed from the incubator during incubation.
Cloaca: The common external opening for the digestive, urinary and reproductive tracts of the fowl.
Coccidiostat: A drug usually added to the feed and used to prevent the disease coccidiosis.
Cock: A male that has finished one season as a breeder. Usually refers to older birds.
Cockerel: A young male from day old to the end of it’s first year of breeding. Often used to refer to young males up to 6 months of age.
Controlled environment housing: An intensive housing system where the operator can control temperature, air quality and light.
Crop: An organ, a part of the oesophagus, located at the base of the neck and used as a storage place for food after eating but before digestion.
Crossbred: A bird with parents of two or more different genotypes (or breeds or varieties).
Crude protein: The nitrogen sources in feed. It is not true protein, as nitrogen is found in dietary compounds other than protein.
Cull: The identification and removal of non-productive birds from the flock.
Cuticle: The outer membrane or bloom on the egg’s shell.
Dead-in-shell: Chicks that fail to hatch from the egg.
Deep litter: The system of housing where a suitable material called litter is provided on the poultry house floor for the birds to live on.
Disease: Any condition that affects the proper functioning of the bird’s system(s), organ(s) or tissue(s).
Dry bulb thermometer: A thermometer with a dry, uncovered bulb used to measure temperature.
Egg bound: An afflicted hen is one that is unable to complete the egg formation and laying process and retains the partially or fully formed egg in the oviduct.
Embryo: The developing chicken in the egg.
Free range housing: A system of housing where the birds have a shelter house and access to an outside area during the hours of daylight.
Feed hopper: A semi-automatic feeding system which has the capacity to hold food in addition to that in the feeding trough associated with the feeder.
Fertile egg: Those eggs in which fertilisation of the blastodisc has occurred to create the blastoderm. Resulted from the joining of the female ovum and the male sperm to create the embryo.
Flighty: Excitable flock inclined to fly at the slightest provocation.
Flock: A number of birds of the same origin (genotype), age and managed in the same way.
Feed conversion ratio: The relationship between feed production and production (eggs or growth). It is usually expressed as a ratio.
Floor eggs: Eggs laid on the floor of the shed and not in designated nest sites/ boxes.
Fowl: The term used to describe all members of Gallus domesticus (domestic fowl) irrespective of age, sex or breed.
Germinal disc: The fertilisation site on the egg yolk. Alternative names include blastodisc and blastoderm.
Germicidal solution: A solution of chemicals that will kill microbes.
Gizzard: The muscular stomach of the fowl where the food is ground and mixed with the digestive compounds produced by the proventriculus (glandular stomach).
Growers: The term used to describe all stock between the end of brooding and till they reach sexual maturity.
Hatchability: The number of saleable chickens that hatch from all eggs incubated – usually expressed as a percentage.
Hatch of Fertile (HOF): The number of saleable chickens that hatch from all eggs classified as fertile.
Hen: A female after the first moult. It is often used to describe females after they have started to lay.
Hen day average: Progressive egg production record calculated on a survivor basis and expressed as a percentage.
Hen housed average: Progressive egg production record calculated on the basis of the number of birds placed in the laying house at point of lay.
Hock: The joint of the leg between the lower thigh and the shank. It is most commonly the region where the feathered portion of the leg ends and the scaly shank of the lower leg starts.
Hover: A canopy used on brooders to direct the heat downwards to the chickens.
Incubation: The process by which fertile eggs are subjected to conditions suitable for the initiation and sustaining of embryonic development and the hatching of strong, healthy chickens.
Incubator: The machine used to incubate fertile eggs.
Insoluble grit: Hard, insoluble material such as granite, flint or bluestone chips consumed by the birds to aid in the grinding of the food in the gizzard.
Intensive system: Any system of housing poultry where the birds are indoors all of the time and do not have access to the outside. It usually entails higher stocking densities.
Keel: The breastbone or sternum of the fowl. This bone has a large surface area to provide for the attachment of the large muscles of flight (the breast muscles).
Layer: A female in lay. Usually used to refer to females kept solely for egg production for human consumption.
Layer cycle: The period from the onset of lay until the natural moult causes a cessation of production. Usually used to describe the period during which an economic level of production is being maintained.
Lighting (artificial): The use of controlled artificial light to regulate the day length under which the stock are kept.
Liveability: The expression used to describe the number of survivors in a flock.
Lux: A unit of illumination equal to one lumen per square metre. Used to measure the brightness or intensity of light.
Meat chicken: See Broiler.
Metabolisable energy (ME): The energy in a food ingredient or diet available for metabolism (used by the animal for normal body functions and activity).
Metabolism: The sum of the chemical changes in living cells which provide energy for the vital activities and processes of the body.
Methionine: One of the essential amino acids.
Micro-ingredient: An essential ingredient in the diet that is required by the bird in very small quantities.
Moult: The process whereby the bird sheds its feathers and ceases egg production. It is usually initiated by hormonal influences but is often triggered by stress.
Peck(ing) order: The social organisation of a flock ranging in a ladder formation from the most dominate to the most subordinate member of the flock.
Pendulous crop: An enlarged crop usually due to impaction and which hangs downwards in an abnormal way.
Perchery system: A system of housing consisting of a litter floor plus a number of perches installed to increase the number of birds that the house will hold. Some of the perches carry feeders and drinkers.
Point of lay: Females just prior to starting to lay.
Preen gland (uropygeal gland): A gland located at the base of the tail which produces a special “oil” secretion for the conditioning or preening of the feathers.
Primaries: The ten long, stiff flight feathers at the outer extremity of the trailing edge of the wing. They are separated from the inner group or secondaries by the “axial” feather.
Production efficiency: The relationship between the various major production factors which, depending on the class of stock, will include feed consumption, live weight gain, egg production and mortality.
Proventriculus: The glandular stomach of birds located in front of the gizzard.
Pullet: A female in her first laying season. Often used to refer to young females post brooding to point of lay.
Purebred: A group of birds having the same origin, and able to reproduce their own likeness in their offspring. Purebred birds have the same genotype, but all birds with the same genotype are not necessarily purebreds.
Relative humidity: The percentage of moisture saturation in the air. There is a direct relationship between temperature and relative humidity – as the temperature increases, the relative humidity decreases and as temperature decreases, the relative humidity increases.
Roost: The perch on which fowls rest or sleep.
Rooster: Male bird.
Sanitise: That part of the cleaning procedure aimed at killing as many microbes as possible.
Secondaries: See Primaries.
Semi-intensive: A system of housing where the birds have access to a shelter house and an outside run enclosed by a fence to keep the birds in and predators out.
Sexing: The act of dividing the flock into its component males and females.
Skillion roof: A roof with a single pitch or slope.
Slatted floor system: A system of housing similar to the litter system except that wooden slats approximately 2 cm wide with a similar gap between are used instead of litter. The faeces pass through the gaps and out of reach of the birds housed therein.
Slave hopper: The short term food holding hopper integral to the food delivery system of a mechanical feeding system and additional to the main food storage silo.
Soluble grit: Various sources of calcium in the diet – usually a granulated or grit form of limestone.
Spent hen: A layer that has reached the end of her economic egg laying life.
Started stock: Layer replacements post brooding to point of lay.
Stubbing: Removal of the short stub or pin feathers after plucking.
Thermostat: A device sensitive to temperature and usually used to control the operation of temperature modifying equipment.
Vent: The common external opening from the cloaca for the digestive system, urinary system and reproductive system.
Vitamin/mineral premix: A concentrated source of various vitamins and/or minerals mixed together so as to make the adding of them to the diet much easier (beware of antagonistic materials).
Wet bulb thermometer: A thermometer with a wick covering the bulb. The wick keeps the bulb wet by drawing water from a reservoir. Used in conjunction with a dry bulb thermometer, a reference to appropriate tables comparing wet and dry bulb readings will indicate the relative humidity.