As poultry production is a prime example of a vertically integrated agricultural industry, with intensive rearing systems of birds of efficient feed conversion ratios and products of handy size and ready marketability, it is not surprising that it is currently showing the strongest growth in output of any category of meat. World-wide, it is a huge industry. Estimates of poultry populations are detailed in Table 1. The largest increase in poultry populations between 1979 and 1989 are in N&C America, S America & Asia. As a general rule, poultry populations in developing countries are rising at a faster rate than in developed countries.
|1979||1987||1988||1989||% increase 79–89||% increase human pop 79–89|
Source: FAO Production Year-book
Because poultry has a very short life cycle and poultry products are traded internationally, data on regional flock sizes are difficult to interpret. Estimates of world poultry meat production in metric tonnes are detailed in Table 2.
The largest increase in poultry meat production took place in S America, particularly in the mid 1980's. The increase in developing countries has generally been higher than in developed countries but the impact is reduced because the increase in human population has been greater. Poultry production is three times population growth in developed countries but only double population growth in less developed countries.
|1979||1987||1988||% Increase 1989||79–89||% increase human pop 79–89|
Source: FAO Production Year-book
Estimates of world poultry consumption are detailed in Table 3. Levels of poultry consumption are increasing throughout the world and the increase in developing countries is about double the world average. This has been achieved through increased local production which has kept pace with demand.
|1979||1987||1988||1989||% increase 79–89||% increase human pop 79–89|
Source: from FAO Production and Trade Year-books
The recommended average daily intake of protein is 0.6g/kg body weight or 12–60g per day depending on age and weight. Poultry products such as chicken have a high protein content.
Table 4 shows the % protein content of some common foods and their consumption. The table shows that the less developed countries appear to consume sufficient protein. A better interpretation would be that there is sufficient protein available for all to eat. In practice, protein distribution is skewed in Idc's so that some areas have plenty whereas others have very little.
|% Protein||Consumption in kg dry matter/head/yr 1989|
Source: from The Report of the Scientific Review Committee, 1990, Health and Welfare, Canada
Although this document concerns slaughter and processing for meat production, poultry are also kept for their eggs. Eggs are a highly versatile food containing many essential nutrients. They are classified in the same protein food group as meat, poultry and fish (see Table 4). In developed countries per capita consumption of eggs has remained almost static over the last ten years but in less developed countries has risen by 37%, about 1.5 times faster than population growth. This has been achieved through improvements in local production rather than increased importation. This indicates a sharp increase in poultry husbandry skills and readiness to undertake intensive production. The flocks used for both table and hatchery egg production are found in significant numbers and eventually end up at poultry processing plants.
The outlook for world poultry production is for continued strong growth. Poultry production is projected to continue to expand in N&C America and the EC. Further growth in Asia, particularly Thailand, is expected as a result of strong demand from Japan and the development of the EC market. Growing domestic demand in Brazil & China should result in higher production levels. In the old Soviet Bloc and eastern Europe, production is projected to fall as a result of reorganisation following market liberalisation. Demand in less developed countries will continue to grow at least apace with population.
|1979||1989||% increase 79–89||% increase human pop 79–89|
Source: FAO Production & Trade Year-books
There are many species and breeds of poultry which are used by man. Some are of more importance than others. The domestic chicken (Gallus domesticus) has assumed World-wide importance and accounts for more than 90% of the world's poultry flocks. Ducks account for about 5% of the world's poultry flocks and turkeys for about 2%. Table 6 details % world distribution of the three most important poultry species during 1989.
Other poultry species of lesser world importance are geese, guinea fowl, doves, pigeons, pheasants, quail and ostriches. It is estimated that together these species account for less than 3% of the world's poultry flocks.
Source: FAO Production Year-book
Poultry raising is classified into intensive or extensive systems. Where movement is restricted and birds are kept close together at elevated temperatures, broilers grow rapidly to market weight. In these intensive rearing conditions chickens (broilers) are ready for slaughter in 8–12 weeks and weigh 1.6–1.8 kg. Ducks or ducklings are ready in 8–12 weeks and weigh 1.7–4 kg. Turkeys are ready in 12–30 weeks and weigh 4.5–15 kg.
Intensive rearing systems are usually constructed on hen houses of 8 × 25m which contain 1000 birds per unit. Each producer has many units and contracts to sell his birds at a given weight on a given day. His day - old chicks, feed supplier, veterinarian, transport of birds to the abattoir etc are all programmed to meet a predefined production schedule. These intensive systems are highly programmable, predictable and cost effective.
The intensive system of poultry production prevents or minimises exposure to natural conditions. The extensive system permits the fullest exposure to natural conditions. Where the flock is allowed a free range, feed inputs are used by the bird for exercise and maintenance of body temperature before meat production. Social interaction and the stresses of everyday life use up food energy. This may be regarded as an inefficient production system.
Where extensive systems are practised, the birds are left to scratch for food. This appears cheaper than intensive systems but slaughter weight/time is much more difficult to predict and the system generally can not be used as a basis of contract between producer and meat packer.
In the developed world it is estimated that in excess of 95% of the worlds poultry flocks are reared under intensive conditions. In the developing world the extensive systems are the most usual practices. While this may be due, in some instances, to a lack of poultry management skills, knowledge, infrastructure, capital etc, it may be a natural reaction to the tropical climate.
Poultry have an internal body temperature between 41.2 and 42.2°C, which is about 2–3°C higher than that of mammals. Chicks have a body temperature about 2–3°C lower than that of an adult bird but the adult temperature is reached within about a week of hatching. The major problem poultry have when exposed to temperature extremes is to maintain efficient functioning of their metabolic processes. The relatively high body temperature maintained by poultry means that they are significantly more vulnerable to extremes of heat. This is because they maintain a body temperature only 3–5°C below the temperature at which protein inactivation starts. In poultry production, birds kept within the range 21–26°C at humidities within the range 50–90% will give the highest levels of food conversion into growth. However, at higher temperatures (about 30°C) humidities within the range 30–70% have been shown to reduce growth rate.
Under intensive rearing conditions poultry can suffer extreme levels of stress due to the environment in which they are reared. The close proximity of birds raised in an intensive system inevitably affects their social organisation. Poultry can suffer damage in various ways including disease, attack by predator, cannibalism and feather packing all of which can lead to a reduction in productivity and income. Under extensive conditions social organisation generally remains well structured and much of the damage and stress associated with intensive rearing is absent.
While there is a strong market demand and a continuing increase in production skills, further expansion of the industry is dependent on continued and improved availability of capital (for infrastructure, marketing and working), poultry feedstuff of the appropriate quality, integration of all systems from egg fertilization to consumption of product, management and business acumen, skilled labour, marketing (in terms of quality, consistency and continuity of product) advice and provision of quality, disease - free chicks.
Disease is a major hazard in poultry rearing, particularly with the growth in numbers of large scale processing enterprises. Hygiene is a most important factor in disease prevention. Efficient cleaning can eliminate over 90% of all diseases and there are other measures which can be taken to prevent disease and its spread among the flock. These are given in Chapter 4.
Whereas it is not practical to expect a veterinarian to examine each bird on the farm before it leaves for the poultry processing plant, it is the producers responsibility to ensure that the birds are healthy as far as the producer can tell. Sick birds should not be sent for slaughter. They should be disposed of at the farm under veterinary supervision if possible. The circumstances of the sickness should always be reported to the veterinarian.
Transportation of live birds to the slaughterhouse involves the possibility of contamination, especially if cleaning and disinfection is insufficient and the same cages are used for several different flocks. There are several precautions that should be taken regarding vehicle and transport hygiene. Cleaning and disinfection of cages should be carried out after use and if cages are not used for some time then the process should be repeated as contamination may occur in storage. The vehicles which carry the modules or cages should also be cleaned and disinfected after use.
Good personal cleanliness and habits are of the utmost importance in maintaining high standards of hygiene in a poultry processing operation. Staff are involved at all stages of processing and the provision of cleaning facilities and materials together with a policy of staff training in hygienic practices will form the basis for achieving high standards of hygiene.
There are many systems for poultry harvesting. The most common method for small scale operations is for broilers to be caught by hand and then carried to the transport by one or both legs. This procedure requires great care as it can cause dislocation of the hip - joint, internal bleeding and even death.
In larger scale operations, herding, sweeping and vacuum systems of harvesting have been developed. In the first, birds are herded into a mechanical handling system by catchers onto a conveyor belt The birds are then blown into a crate. The sweeping system uses a machine fitted with a central boom and sweeper arms fitted with rotating, foam rubber paddles, which gently sweep the birds onto an inclined conveyor. The vacuum system relies on gentle suction from the floor. Crates are then filled by a mechanical device.
Some birds are marketed as individuals but others are contained in crates which are either loose or fixed to the truck or as a module of 4–16 crates carried by fork lift truck to the vehicle.
Poultry are transported to market in various ways. In rural areas live birds are taken to market by individuals, using any form of available transport. Farmers or small cooperatives may organise transport on a more formal scale using trucks and pick-ups. Large scale poultry processing companies generally have their own transport as part of their intensive rearing operation or outside haulage contractors may deal with this aspect of their processing operation.
At the general market, birds are usually displayed tethered, hung by their legs or in their crates. Live poultry is bought by the consumer who may take it home to be slaughtered, it may be slaughtered at the market stall or in a specially designated place nearby. These slaughter methods have hygiene and health implications which this document seeks to address.
On a small scale level at market, birds may be sold by the producer to individuals or butchers. Farmers or small cooperatives may sell their produce at market by auction or direct to slaughterhouses or meat processing companies under contract arrangements. Poultry processing companies involved in rearing, processing and marketing poultry are generally not involved in the sale of live birds at market.
Large scale poultry enterprises contract farmers to produce birds for them. They contract or own transport to get the poultry to their processing plant. The large scale processor operates his own abattoir where he slaughters, processes, grades, packages, stores and distributes poultry either for his own use or under contract to other large organisations, such as supermarkets. The large scale operator employs his own staff, is responsible for procurement, (or contracts this to a specialist) and is responsible for waste disposal. The whole operation is highly efficient and integrated with all parts of the poultry production, processing and sales industry.
Medium scale operators use similar facilities and staff to slaughter for several organisations who have responsibility for procurement and transport. They may prepare a product to a customers specification.
Small scale poultry processing enterprises, the subject of this document, may use their facilities and staff as described for the medium scale operators. However, the operators may allow the producer or butcher to slaughter his own livestock or contract labour to do so on his behalf. It is best for the small scale operator to employ his own labour or contract this to a well respected contractee and charge the customer a slaughter fee. The customer takes away his poultry and is able to sell it as he wishes, either through direct sales to the consumer or by wholesale to retail outlets or to other poultry users, such as fast food establishments or poultry product manufacturers.
Birds are usually raised as the property of the poultry producer such as an individual farmer, farmer cooperative, meat processing company or poultry processing company. Legal ownership rights usually change when birds or carcases are bought or sold. When birds are sold by contract or auction the producer usually relinquishes all rights of ownership. Small scale producers are sometimes integrated into large poultry processing enterprises by contract, which may result in birds being the property of the large enterprise throughout ie the producer is contracted to grow the birds without actually owning them. However, if poultry producers hire abattoir facilities and/or staff to slaughter their own birds, rights of ownership may be retained. The birds are then marketed as a completely processed product or they are sold to a food marketing company. Large scale poultry processing companies usually retain all legal ownership rights until the product is sold to a food distributor or shop. In some cases company ownership rights are relinquished only when the product is sold to the consumer.
Ownership is important because the system of payment to the producer at the point of change of ownership can act as an incentive to grow better poultry. Live birds can be sold by the head (no added incentive) weight (a fair system with minimal incentive) by carcase weight (fair, providing an incentive if a weight/price scale is introduced) or carcase weight combined with a grade to which a price is attached (providing maximum incentive).
Modern abattoir poultry processing is generally almost fully automatic. In large and medium scale operations, staff hang birds upside down by their legs from an overhead conveyor which then carries them through a highly organised processing system. They are electrically stunned and killed, scaled and defeathered by machine. In larger scale operations automatic evisceration machinery is used. In medium scale operations of up to about 1000 birds/hour, evisceration, neck and gizzard removal is manually carried out with the aid of labour saving tools and equipment. Automatic weighing and grading systems are also available and packing is semi-automatic with a packing machine controlled by an operator.
In small scale poultry processing operations, slaughter is carried out manually using simple processing equipment. Stunned poultry are held in a bleeding cone, with the head & neck pulled downwards through the opening in the cone. With a typical turnover of up to 500 chickens per hour, plucking is effected dry, most often by hand on a special machine. In operations over about 50 birds per hour, a wet scald system may be used. Pin feathers may be removed by hand or hand held to a simple machine and evisceration is carried out on an overhead rail, carousel or table unless the poultry is to be sold New York Dressed ie defeathered only.
In all operations, carcases are spray washed and chilled rapidly before dispatch or further processing. Carcases and their giblets are reunited in some plants before they are packed, chilled or frozen. Some carcases are processed further into portions or poultry products.
Processed poultry is prepared in many forms. Poultry is mainly available fresh, frozen or canned, sometimes in combination with spices and other foods eg chicken curry, as whole carcasses, parts such as leg, breast or wing deboned or bone-in. Poultry meat is also converted into manufactured food products, either alone or in combination with other ingredients eg pate, sausages, cured roll, cooked and raw, ready battered for the fried chicken trade.
Poultry packaging protects the product from contamination, damage and moisture loss. It can also extend the shelf-life of the product, improve product presentation and consumer appeal. Packaging methods, are discussed in more detail in Chapter 3.
The primary aim of meat refrigeration is protection against spoilage by micro-organisms. Refrigeration also gives a measure of protection against other forms of meat deterioration such as fat oxidation. Refrigeration is of great importance both during and after poultry processing. This is explained in greater detail in Chapter 3.
Transport of the processed carcasses, parts or products is usually by refrigerated truck. However, where refrigeration is not available the product may be processed at a time when they may be easily sold at market quickly or to coincide with a festival or celebration. In this case transport may be an unrefrigerated truck or motor vehicle, horse & cart, bicycle or even by man on foot.
Poultry products are displayed in several different ways. Whole carcasses are often displayed unrefrigerated at market in the open hung by their legs or on a stall or shop display, particularly in the developing world. This is not to be recommended. Refrigerated products are displayed in shops and other retail units unpackaged or over-wrapped on plastic trays. In some are as meat is sometimes sold from mobile refrigerated shops. Products are usually exchanged for cash at the point of sale. However, poultry producers may have contracts with poultry processing enterprises, local hotels or restaurants where a lump sum payment is made. In developing countries small scale producers may sell by bartering for other consumable items.
Poultry is one of the most widely accepted meat foods in the world and is not subject to any religious restriction. Consumers recognise poultry as a relatively cheap protein source. In developing regions, poultry meat may be seen as food for a special occasion, but figures indicate poultry meat consumption is increasing in these regions. Poultry may be reared and killed in time for a celebration or special event. In some regions turkeys and geese are reared for thanksgiving and Christmas celebrations, although successful marketing has made it a popular choice at other times of the year. Chilled and frozen carcases or parts can be stored for longer periods and use becomes more convenient and regular. Some regions of the world have a preference to particular type of poultry; for example, in Asia, ducks are most popular. The type and use of food products made from poultry meat is also increasing throughout the world. These include roasts & rolls, turkey ham, smoked turkey and stuffed breast portions such as chicken Kiev. Changing lifestyles have brought about an increase in the number and type of poultry fast food products. In the developed world the number of women in the workforce has increased and home cooking from basics has been greatly reduced. Products such as fried chicken and chicken nuggets are sold by fast food franchises, particularly in N. America, Europe and Asia. In Japan yaki-tori is a very popular fast food product consisting of grilled chicken cubes on a skewer with yaki-tori sauce. A visit to the large towns and cities of the developing world will demonstrate that these products are transferring quickly.