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Chapter 9: Marketing

As a country develops, more of its consuming population lose touch with the village and food producers. Thus more specialised marketing services are needed. Farm produce must be collected, packed and transported in good condition to the cities and distributed to retailers near consumers’ homes. This also calls for grading and storage of the product. The more developed the country becomes; the greater is the variety of products that can be economically produced. All this must be provided at a cost that consumers can afford.

A study of existing marketing systems in a country will often reveal how they have evolved to their present state. Many developing countries do not have refrigeration as a factor in their storage, either during transport, retail or consumer household stages. For this reason, poultry meat is purchased live, and slaughtered immediately before consumption. Also, eggs are often retailed with a means for the buyer to check their quality before buying, either by “candling” (to see the internal quality with a lantern or battery-torch) or a bucket of water (to test the egg’s age by the floatation method). Both methods essentially test for the size of the air-cell situated at the blunt end of the egg, which increases in size as moisture is lost from the egg. With a bigger air-cell, there is more floatation.

In developing countries, transport of eggs and poultry from the village to the city usually begins with a purchase by a middleman dealer, direct from the household, or from small locally held weekly markets. Baskets with layers of straw protect the eggs from breakage, and other types of baskets are used to carry live birds. Bullock carts are still used in many countries for transport of both live poultry and eggs to larger community centres. The roofs of buses or trains replace these slower vehicles as transport systems develop. Marketing quality considerations for live birds are usually concerned with weight loss in the bird from dehydration during transport. These are easily resolved by providing drinking water during the trip, and travelling during the cool part of the day when possible. Egg quality considerations are more complex and are dealt with in the second half of this chapter.

Improved marketing programmes must add no more cost to the product than the consumer can afford. Important marketing improvements can often be simply made by making small corrections to already existing handling, transport, packaging, grading and storage methods.

Marketing organisations generally come into being very gradually, and must be appropriate for the background, character and education of the people concerned. Plans for radical changes, which do not take sufficient account of social and economic environments, are likely to fail. Thus any improvement programme should be designed to achieve desirable modifications in existing commercial facilities (and their economic and legal framework) by a process of steady growth.

As a country develops, the task of marketing eggs and poultry will still involve the collection of live poultry and eggs from farmers, transporting them to a grading, packing or processing plant, grading and standardising the poultry meat and eggs, processing them and packaging them into more useful forms, storing them (preferably under refrigeration), moving them through wholesale and retail channels and delivering them to consumers at a convenient time and place.

This chapter provides a brief outline with some practical information and advice to those who are immediately concerned with egg and poultry marketing considerations. For a more detailed examination of marketing, the reader is referred to FAO Marketing Guide N° 4 "Marketing eggs and poultry" (1961), from which some of the following material is taken.


Ceremonial and traditional aspects

In traditional societies, poultry are often used for ceremonies, sacrifices and gifts. What follows are some traditional aspects of poultry keeping from the Mossi of Burkina Faso (West Africa), the Mamprusi of northern Ghana, and Bangladeshi and Malay farmers in South Asia.

Among the Mossi people when no poultry is available (such as after a Newcastle Disease outbreak), to meet customary family obligations, the household must purchase or borrow a bird. Chickens are given to convey value to a relationship, or to offer thanks for a favour or help (such as from government officials). For most socio-cultural and religious purposes, the required sex and colour of fowls are also prescribed. For example, a family will give a white cockerel when an agreement for marriage is reached.

The consumption of eggs in Mossi villages is uncommon. There is a strong belief that a child who regularly eats eggs will become a thief, reasoning that the good taste of eggs will make the child want to eat eggs often. The only eggs consumed are those that fail to hatch under broody hens. These are boiled and then eaten. Chicken eggs, unlike guinea fowl eggs, are not part of the trade in poultry products, since all eggs are required for hatching to maintain the flock (given the normally high losses during rearing). Dealers from urban areas reflect the demand for village eggs. The eggs are often bought by small food stall merchants who boil the eggs and resell them as snack food. A considerable number of guinea fowl eggs are collected by the Mossi for sale, most of which find their way to the cities via village markets, where dealers buy the eggs.

The Mamprusi society in northern Ghana has a variety of uses for poultry products. Chicken cocks are the most popular sacrificial animals. Guinea fowl cocks are not used. The colour of the bird is important. A red cock is sacrificed to ask for rain or a good harvest; a white cock is used to convey value in relationships, and a black cock is used to ask for protection against disease, war or quarrels. Because of these customs, red, white and black cocks have double the value of cocks of other colours.

The sale of young birds and eggs takes place in the Mamprusi village markets. Prices fluctuate during the year, and are low during the pre-harvest season, when the granaries are empty and the crops are still growing and thus cash is less available. At such times, traders from the south come to buy for resale in the cities. Sometimes, middlemen dealers are involved. They buy the birds in the villages and sell them at markets or to city-based traders. The sale of poultry products from Mamprusi households contributes about 15 percent to Mamprusi annual cash income.

Poultry consumption by the household is rare, as most birds are sold for income generation. In Mamprusi society, women, circumcised girls and first-born children do not consume eggs or meat. These products are only eaten by elderly men, male visitors and young children. The reasons are not fully understood. Some Mamprusi women believe that during pregnancy, their behaviour (including their food choices) can affect their unborn child.

In Bangladesh, eggs and meat are consumed mainly by men and boys, and very rarely by women and girls. Low-income groups generally do not consume eggs or meat. These products are sold, and from the proceeds, essential items are purchased, such as carbohydrate and low-cost vegetable protein foods.

Guinea fowl, more than chicken, are given as gifts to visitors. To give a gift is considered to be a wealth-increasing action as well as an act that conveys value on the receiver. Farmers often save for agricultural equipment or other materials and small livestock is used as a savings account. The offspring, like chicks, are considered to be the interest on the savings.

In many parts of Africa, birds are sold to meet unforeseen expenses, for example, to buy the beer and kola-nuts customarily given to gravediggers when a family member dies. The birds usually sold from the village flock are: surplus males (cockerels and cocks); pullets; old hens; non-productive hens; large-sized birds and sick birds. Young birds are often sold just before the onset of the high-risk period for Newcastle Disease.

Traditional taste values placed on poultry meat

It is important to understand traditional taste values and their effect on market demand. The market price for free-range birds for meat is usually stable because:

In eastern Asia, it is believed that chickens fed with chemicals and drugs have poorer therapeutic value, as they do not combine well with ginseng and other oriental herbs used in making soups, especially steamed types. For this type of soup, younger pullets are preferred and thus they fetch a higher price than do the cockerels. The female is said to be more beneficial and the meat tastier. Steamed chicken soup is believed to provide virility and vigour. It is commonly recommended in Malaysia for pregnant women and for those recovering from sickness.

In the case of large-scale commercial ayam kampung (local village chicken) production in Malaysia, local birds are confined and fed on commercial rations but they fetch lower prices than free-range local birds. Such large-scale production has an affect on the market value of all local birds, as purchasers have difficulty distinguishing between genuine free-range and commercially fed local birds. However, the price of ayam kampung continues to hold a margin above that of commercial meat chickens. The introduction of more appropriate methods of Newcastle Disease vaccination in Malaysia will reduce mortality at the village level which may also stimulate further interest in family poultry production. If this happens, there will be an increase in the supply of local free-range poultry products to the market, and the price of the ayam kampung product (from large-scale commercial production) may fall further.

Carcass parts and organ meats

The value of birds for sale in developing countries depends firstly on the available supply, secondly on the age and sex of the birds, and thirdly on their size or weight. Young birds, especially cockerels up to six months of age (weighing up to one kilogram live weight), are usually preferred by consumers. This is because larger birds are more expensive for most households, and smaller birds are more tender and have the same preferred portions (drumsticks for example). Table 9.1 shows carcass characteristics of the local village chicken in Bangladesh.

Table 9.1 Product characteristics of indigenous scavenging chickens in Bangladesh



Live weight, kg


Carcass weight, %



35 - 45

Egg weight, g

35 - 39

Hatchability of eggs, %

84 - 87

Source: Ahmed, 1994 (Bangladesh Livestock Research Institute)

Whatever the size of bird, all chickens have an equal number of high-demand portions (such as breasts and drumsticks), and a similar proportion of gizzards and other desirable organ parts (see Table 9.2).

Table 9.2 Organ weights and carcass composition of Ethiopian local chickens at different ages

Slaughter age (months)

Body part weight (grams)





Total body








































Total organs





Body weight %





















Total Carcass





Body weight %





Source: Forssido, 1986

Buying small birds supplies the same number of the desirable parts for a lower price. Together with the tenderness of the meat, this explains the heavier trade in young birds, which are also bought for replacement stock in depleted flocks.


Depending on the location of the farm dwelling, birds and eggs are sold from the household to traders (dealers or middlemen), direct to consumers, or carried by the farmer to the local market. The role of traders in the marketing of poultry products is an important one. Traders from urban areas buy eggs in villages to sell in cities. Where transport is an important consideration (as in many parts of Africa), guinea fowl eggs, with their stronger shells, are preferred to chicken eggs. Prices of eggs are related to supply and demand, to the higher risk of spoilage and lower use for hatching in hot and humid seasons, and to the availability of alternative protein foods such as fish. There is a tendency to hatch less in the hot season, due to low hatchability and diseases of young chickens, and there is also less hatching in the cold season, due to the risk of chilling stress to the young chicks.

Birds are either brought to the local market once or twice a week for sale to local consumers, to other local markets, or to local traders. Chickens are transported to the market in open-weave (well ventilated) baskets or wooden crates. They need not be fed on the day of sale, but should receive drinking water. If the trip to the market takes eight hours or more, stops should be made to supply water to the birds. In hot seasons, it is better to transport birds at night or in the cooler early morning. While the price of live birds depends on their size, the price of eggs depends more on number.

It is often assumed that for poultry and eggs, producers get 60 to 65 percent of the market price but this has been found to be false in Bangladesh, where they receive less than this. The role of traders or hawkers is very important, as it makes selling from the house possible, but these traders take up to 35 percent of the market value, with a consequent lower profit for the farmers who are responsible for production. This loss of income has stimulated farmers in many places to organize sales through their own marketing groups or formal cooperatives.

Supply channels

A study by Adeyanju et al. (undated, unpublished monograph) of the marketing of poultry products in Ondo State (in south-western Nigeria) revealed a large number of transactions and participants. The typical flow of the products from the producer to the consumer is shown in Figure 9.1. The local channel begins with the producer selling poultry products to retailers who serve the needs of local consumers. In most areas, local consumers also buy directly from producers. The other marketing channel involves wholesalers. They buy poultry products directly from producers and sell to retailers inside and outside the State, and are based in urban centres where urban-based consumers are located.

Fig. 9.1 Supply channel for poultry products in Ondo State, Nigeria



















Source: Adeyanju et al., (Poultry Farming in Ondo State, undated, unpublished monograph)

Odi (1990) found that marketing channels for family poultry often cross international boundaries and can generate significant foreign exchange for the producing countries (see Figure 9.2).

Figure 9.2 Supply channels into Côte d'Ivoire for guinea fowls produced in Burkina Faso







MERCHANTS (250-500 birds)


OUAGADOUGOU (5 000 per trip)

Railway Station

<25% mortality

ABIDJAN, Cote d'Ivoire (3 750 birds)

Railway Station



Source: Odi, 1990


Forming a marketing plan means identifying where and when birds and eggs will be sold to receive the best possible prices. Putting large numbers of birds up for sale in a small community may depress the price.

Even the sale of small numbers of intensively managed layers needs advance planning. A flock of 20 hens may produce 1 200 eggs in a year, even at the low production rate of 35 percent. The plans of other farmers must also be considered. If they all expand their flocks and have good years, prices will almost inevitably fall. Seasonal considerations enter into market plans as well. In India for instance, eggs are thought of as a heat-producing food and are eaten in the cool, rainy season. Many factors affect the quality of eggs (see Tables 9.3 to 9.6) and hence the price that consumers are willing to pay for them in the market.

Table 9.3 Egg quality parameters for four breeds of chickens


Nigerian Local

Isa Brown


Ethiopian Local

White Leghorn

(Asuquo et al., 1992)

(Forssido, 1986)

Egg wt., g



Egg wt., g



Yolk, %



Yolk, %



Albumen, %



Albumen, %



Shell thickness, mm



Shell thickness, mm



Yolk index



Fertility, %



Albumen index



Hatchability %



Haugh unit



Haugh unit



Table 9.4 Length of lay and egg quality in Nigerian indigenous chicken


Months of Lay







Egg wt, g







Yolk wt, g







% Albumen







Shell thickness, mm







Source: Olori and Sonaiya, 1992b

Table 9.5 Quality of eggs of different shell colour of the Nigerian indigenous chicken



Light Brown


Egg wt., g




Yolk wt., g




Shell wt., g




Albumen wt., g




Shell, %




Yolk, %




Albumen, %




Shell thickness, mm




Surface area, cm2




Source: Olori and Sonaiya, 1992a


Quality determines the acceptability of a product to potential purchasers. The quality of eggs and the preservation of this quality during storage is a function of their physical structure and chemical composition. A basic outline of the most important factors of concern in egg quality is presented below.

Egg composition

The egg consists of shell, two shell membranes, the white (or albumin) and the yolk. The shell is quite porous to air and water vapour but is very resistant to invasion by micro-organisms as long as it is clean and dry. A thin outer covering on the shell called the “bloom” or “cuticle” (which is unfortunately easily removed by washing), assists this process. After the egg is laid, its contents shrink, both from cooling and water evaporation. Air is drawn in (along with anything else on the shell, such as bacteria or fungi) through the pores in the shell to replace this loss. A gap opens up between the two membranes because the outer one is attached to the shell and the inner one is attached to the egg white. This gap is known as the “air cell” and is usually found at the large blunt end of the egg. The egg white takes the form of a “thick” albumin sack enclosing the yolk, with a more fluid “thin” albumin between this sack and the yolk to the inside, and again between the sack and the shell to the outside. These layers provide a barrier to prevent the yolk touching the shell and to provide food for the embryo. Egg white has specific antibiotic effects, which further protect the yolk. Egg white also contains two fibrous cords (the chalaza), which are attached to the yolk and to either end of the egg, which help hold the yolk in the centre and assist in preventing the yolk from touching the shell.

The weight of an egg laid by a local village breed of hen is about 35 g. Commercial hybrids lay eggs of about 58 g weight. The shell comprises approximately 11 percent of the weight of an egg, the remainder being the edible portion. By weight of edible portion, the yolk is 36 percent and the white is 64 percent.

Shell quality

Eggs of unusual shape are more likely to be damaged during the marketing process, and consumers do not like them. Small thin cracks in the shell, which do not leak, are called “checks”. These are usually detected by candling. “Checked” eggs should be sold for immediate consumption, as their storage life is limited. The household usually consumes eggs with leaking cracks, where the eggshell membranes are broken as well as the shell. Brittle, thin-shelled eggs (shells less than 0.35 mm thick) are also unsuitable for transport to market. Dirty eggs must be cleaned by dry or wet methods, and thus have a higher marketing risk because of the removal of the cuticle.

Shell colour is not a guide to egg quality, but there is usually a consumer bias to either white or brown, which must be considered in marketing.

Egg yolk and egg white quality

Consumers prefer the odour and flavour of normal fresh eggs. The yolk should be round, firm and yellow in colour. Local yolk colour preferences may vary and can be easily adjusted by raising or lowering the amount of green leaf material included in the poultry ration or supplement. Egg white normally has a slightly yellow-green tinge and the thick white is slightly cloudy.

Consumers are usually critical of blood or meat spots, which can vary in colour from red to grey, and in size from small specks up to one square centimetre. Blood spots are caused by slight bleeding at the time of release of the ovule (yolk) from the ovary of the hen. They may be found in the white or adhering to the yolk.


The interior quality of eggs deteriorates after laying at a rate depending on time and conditions of storage, such as temperature, relative humidity (RH), and the presence of strong smelling substances or other food items in the storage place. Eggs stored at 27 to 29 oC for 7 to 10 days will show deterioration changes similar to the same eggs stored at minus 1 oC and 85 percent RH for several months. The changes are due to water loss, carbon dioxide (CO2) and the absorption of volatile odours from the environment.

Moisture loss

Since an egg contains about 74 percent water and the shell is porous, eggs readily lose moisture. A weight loss of 2 to 3 percent is common in marketing and is seldom noticed by the consumer. When losses exceed this level, the air cell is noticeably enlarged by shrinkage in the contents of the egg. This loss is reduced if the storage humidity is high and the temperature is reduced. Coating the eggs with oil and other substances can also reduce the loss. The ideal conditions for egg storage are about minus 1 oC and between 80 to 85 percent RH. At storage temperatures of 10 oC and above, the optimum RH is 80 percent. There is a risk of mould spoilage when the RH is too high. Paper pulp egg trays or other packing materials that readily absorb moisture will accelerate moisture losses from eggs. A temperature as low as 10 °C is unlikely to be practical in rural areas of many developing countries. Temperatures between 10 and 15 °C are more practical, but even then, care should be taken when moving the eggs from cool storage into the outside air with its higher temperature, which often causes condensation to form on the shell, with consequent risks of mould and “rot” growth.

Microbiological spoilage

The contents of the egg are usually sterile when the egg is laid. The main cause of contamination is the washing of eggs. Wetting the shell allows micro-organisms on the shell to penetrate and multiply inside. Common indications are green, black and red “rots”, mustiness and sourness. The bacteria causing these effects cannot penetrate the shell if it is kept dry. If eggs do become wet through condensation, for example after removal from a cool store into a warmer room, bacteria may then be able to penetrate the shell.


Eggs, especially yolks, are easily tainted by strong odours, from such sources as disinfectants, soaps, diesel, kerosene, petrol, paint, varnish and wood preservatives. Other foods, such as onions and citrus products, can taint eggs after only a few days of exposure.


Maintenance of egg quality is a major problem for those involved in egg marketing. The importance of using good packing, storage and transport methods to preserve quality is addressed in other sections below.

Eggs soiled by droppings or the contents of leaking or broken eggs spoil faster than clean eggs. Only good quality eggs should be sent to the market. The simplest way of sorting is to divide the eggs into three categories: cracked, dirty and clean. The cracked eggs should be eaten or sold locally for immediate consumption. The dirty ones should be cleaned and sold locally for consumption within a few days, while the clean eggs can be sent to the major marketing outlet. In some areas, eggs of certain colour or sizes are preferred, and the eggs should be sorted for these qualities.

Production factors affecting egg quality

The main production factors affecting egg quality are:

Breed and age of the laying flock

The effect of breed on the egg is inherent in many aspects, including the colour, thickness and texture of the shell, the incidence of blood spots, and the amount of thick albumin. While commercial breeders pay constant attention to these factors, there is little that farmers can do to control them.

After the first season of egg production, hens produce eggs of poorer shell quality and poorer egg white thickness, even though the eggs are larger in size. The rate of egg production is also lower. For these reasons as well as the high meat value of the carcass of the older hen in most developing countries, it is advisable to replace the hens after 12 to 18 months of lay.

Type of feed

A balanced diet supplied to intensively housed chickens must supply sufficient nutrients to enable the hen to produce an egg with a good shell thickness and good egg yolk colour. A high level of yellow maize, leaf or grass meal will ensure a good yolk colour. Calcium carbonate in some form (limestone or shell) must be supplied (for more detail, see Chapter 3 on Feed Resources and Chapter 4 on General Management). This is either mixed in the ration or fed as a separate supplement on a free-choice basis. It is often quite practicable to have a separate container in a pen with shell or limestone inside.

Fish meal with a high fish oil content fed in the diet can give fishy flavours to eggs produced by hens on those diets.

Incidence of disease

The diseases Infectious Bronchitis (IB) and Newcastle Disease both affect egg quality. They cause the hens to lay eggs with misshapen shells and poor quality thick white. IB induces groove-like marks along the long axis of the eggshell.

Management control over the laying flock

In many developing countries, there is a belief that a rooster is necessary to stimulate hens to lay. This is not true. The presence of an active male causes the eggs to be laid as fertile eggs (containing an embryo chick), and this reduces the storage stability of the egg. Even after the male is removed, all eggs laid are fertile for up to six weeks because sperm is stored and released from specialised cavities in the hen’s oviduct. If fertile eggs are in demand, then cocks should be placed with the hens. Non-fertilized eggs have a much longer shelf life than fertilized eggs and are more suitable for the market.

Dirty eggs can be reduced in number. For hens in deep litter systems, the nest box litter must be clean and replaced regularly. Frequent collection of eggs under any housing management system, and at least four times a day in the hot humid tropics, will reduce the incidence of dirty eggs.

Management control over egg handling

Temperature control

The most effective way to preserve egg quality is to store eggs between 10 and 15 oC during all handling, transport and marketing phases. Insulated containers and/or vehicles can maintain cool temperatures during long-distance transport. Even an outer layer of straw in a basket will help. In hot weather, and where there is no cool storage system, eggs should be transported to market at least every third day. Eggs should never be left standing in the sun or in a very hot room. Air conditioning or even an electric fan is advised whenever practicable. However, as air conditioning has the negative effect of drying out the egg contents as well as the advantageous effect of cooling, wet sacks should be placed as curtains in the cool store to alleviate this dehydrating effect. If fans or air conditioning are not available, then shaded well-ventilated rooms or underground cellars should be used.

Treatment of dirty eggs

An egg’s shell has a natural protective coating (cuticle) that resists the entrance of bacteria and retains moisture inside. Washing eggs with water removes this protection, and thus washed eggs should be eaten as soon as possible. Whether eggs are wet- or dry- cleaned, they should be sold separately from naturally clean eggs, as their storage life is shorter. The cuticle from the shell is a protein-fat substance, and the lack of a cuticle can therefore be detected with a simple ultraviolet (UV) lamp. Washed eggs (without a cuticle) are red in colour under UV-light, while a blue colour indicates that the cuticle is still present.

Dry cleaning

Even with good flock management, some eggs will get dirty. The risks of allowing water to touch the shell have already been mentioned. Dry cleaning systems are preferred. Rubbing lightly with fine sandpaper or a rough cloth is better than wet cleaning. Cloth-backed sandpaper or emery paper can be wrapped around a block of foam rubber for dry cleaning by hand. Steel wool and nylon dishwashing or bathroom scrubbing aids are also quite suitable. Care should be taken not to remove too much of the protective cuticle layer which covers the shell. Only the dirty patches should be cleaned. There are also motor-driven dry-cleaners commercially available. The simplest model consists of a spinning wheel of foam rubber. A mixture of glue and sand is applied periodically to the foam wheel. The operator holds the egg against the spinning foam wheel to clean it.

Wet cleaning

Washing of eggs is only suggested under very well-controlled conditions. The concern is to ensure that the washing water temperature (38 to 43 oC) is never below that of the egg. This avoids the wash water being sucked into the egg through the shell pores by the action of the egg contents shrinking (as happens if the egg is in contact with cooler water). In addition, the washing machine must be able to monitor the detergent/sanitizer/disinfectant/antiseptic levels in the water to ensure that they are optimal. Only special types of non-tainting chemicals can be used. The water itself must be changed frequently. After washing, the shell should be pasteurised by dipping the eggs in water at 82 oC for a few seconds, then dried quickly with warm air before packing. The eggs must also be clearly labelled as “washed”. Washing done in this way is complex and expensive, and is therefore only justified in large operations, although even then it involves risks.


Interior quality


Opening the egg by breaking it is the only accurate way to fully check the interior quality. This can only be done on a limited sample basis. “Candling” can show some aspects of internal quality without breaking the shell. It consists of inspecting the egg in a beam of light strong enough to penetrate the shell and illuminate the contents. Various types of lamps can be used but the essential features are similar. An incandescent-type bulb of 25 to 50 watts is enclosed in a casing with light exiting through a round hole about 3 cm in diameter against which the egg is held and turned. The casing usually has another hole to provide light for the operator to see the egg container if the room is very dark. By rotating the hand-held egg close to the hole in the candler, the yolk and egg white quality can be estimated by their movement. Experienced operators can candle 24 eggs per minute. The main points to observe are summarised in the following paragraphs.


Egg white (albumin) characteristics showing good egg quality are thick albumin fullness and albumin transparency. When the thick albumin sack is strong and healthy, it is full and confines the yolk within the various layers of egg white. As the thick albumin sack deteriorates, its contents leak into the thin albumin cavity. The yolk then moves more freely, increasing the risk that it might touch the shell and be contaminated by micro-organisms from outside the shell. A healthy albumin is also transparent. It can become discoloured or cloudy due to rot or overexposure to hot water (partial coagulation) in washing.


Yolk characteristics showing good egg quality are confinement within the thick albumin, a small spherical shape, orange-yellow colour and the absence of spots. As described in the above paragraph, yolk confinement within the albumin protects the yolk from outside contaminants. A small spherical shape indicates a strong yolk membrane. When the egg is exposed to high temperatures and dehydration, the yolk deteriorates and grows larger and flatter. Consumers prefer yolks of orange-yellow colour without spots. Spots on the yolk can indicate: embryo development (reddish colour); blood from the hen’s ovary and “meat” bits from the oviduct released during egg formation (red and brown, respectively); moulds (grey or black); or bacterial rots (blue, violet, green or red). Although consumers prefer yolks with no spots, the only spots that pose any health risk are mould and rot spots.

Air cell

Air cell characteristics showing good egg quality are small size, shallow depth and fixed position at the blunt end of the egg. Small size and shallow depth indicate very little loss of moisture from the egg contents, which in turn indicates freshness (or that the eggs have been stored under good conditions). A fixed position at the blunt end of the egg indicates that the membranes surrounding the air cell have not been damaged (for example, by rough handling).

There is usually a correlation between the depth of the air cell and other quality aspects. However an egg stored at high temperature and high humidity may show a good air cell depth (as the high humidity maintains the egg moisture) but it may have deteriorated otherwise (as a result of the high temperature).

Air cells can be deflated completely or become unfixed and mobile within the egg. The air cell can become filled with albumin if part of the inner shell membrane is broken. If the membrane is merely weakened, the air cell may move freely around the egg. These mobile air cells are often caused by transporting eggs on rough roads or by the egg being stored small end upwards. The egg could be otherwise quite fresh.

Shell quality

Before candling, eggshell quality is assessed, and eggs that are dirty, cracked, thin, rough or misshapen are processed accordingly (procedures regarding shell quality are addressed extensively in the above section on production factors affecting egg quality).


Eggs can be sold by graded size or by total package weight. Selling by graded size involves weighing each egg individually and grading the eggs within certain weight ranges (commonly Small, Medium and Large). They are then packed in cartons of 10 or 12 eggs, and sold according to a price per graded size. Selling by total package weight involves packing the eggs without size grading, and selling the package according to a price per kilogram (like almost all other food products).

Consumers in the more developed countries are accustomed to buying eggs graded by size and boxed into cartons. Grading eggs by size requires complex machinery for grading and packaging, as well as monitoring and testing of all grading machines, and sample monitoring of the various grades at retail outlets.

In developing countries without the capital or administrative capacity to undertake such extensive monitoring tasks, the better option is to sell eggs by total package weight. If a market weighing scale is used to weigh foods such as rice or maize, then it can also be used to weigh eggs so that they can be sold by package weight. Selling eggs by package weight also simplifies the situation where standardization of containers and grades has not yet been developed. It also makes price comparisons between different types of food items much easier for the consumer.

Eggs in most developing countries are sold by quantity rather than by weight, which penalizes the producer of larger eggs. As local breeds of hens usually lay uniformly small eggs, this is not a significant problem. However, as the market grows and a demand develops for different sized eggs based on the availability of commercial hybrids (laying larger eggs) in peri-urban areas, the decision to sell eggs by graded size or by total package weight must be faced.


The four concerns regarding egg transport are:

Egg packing methods

Eggs can be packed with a padding of rice husks, wheat chaff or chopped straw in firm-walled baskets or crates. This greatly reduces the risk of shell damage in transport. In Iran, long flat boxes, each containing about 1,000 eggs cushioned in chopped straw, are commonly used for the transport of eggs to the capital from a distance of up to 1 000 km. The boxes are transported in trucks over rough roads, but breakages seldom exceed five percent. The main difficulty with such systems is in standardizing the number of eggs per container. Consignors and receivers will otherwise spend much time counting eggs and repacking to ensure that the correct number has been received for payment.

The standard type of transport egg packing container is the 30-egg tray, which is made of paper pulp holding six rows of five eggs each. The trays are stackable either when full or empty. A standard box of 360 eggs (30 dozen) is made up of two stacks, each comprised of six trays. Washable plastic reusable trays are also available. Cases are usually made of wood. Half-cases to hold 180 eggs (15 dozen) are also common and are usually made of corrugated cardboard.

Quality preservation during transport

Permissible temperature ranges depend on the duration of transport time. In Europe, the temperature recommendation for two to three day transport in refrigerated vehicles is between -1 oC to 3 oC. In developing countries, however, refrigerated vehicles are not widely available. Even when available, precautions are needed to avoid moisture condensation on eggs removed from the cool container to the warm moist air of the retailing environment.

Fans blowing air towards the eggs across a container of salt and ice is a cooling system that has been used in Pakistan for egg transport by rail for the 1 600 km trip from Peshawar to Karachi, where outside summer temperatures can range from 38 °C to 47 °C.

Refrigerated transport is expensive. In estimating the costs of establishing such a system, the volume of trade for refrigerated goods is an important consideration. The capital cost may be spread over five years to prepare the costing. Transport of other taint-compatible produce with the eggs should be considered; as should the prospect of back-loading with other goods, which may not necessarily require refrigeration.

Public transport such as rail or bus is the most common means of transport in developing countries. Awareness of the special needs for egg transport as addressed above will assist the operator in preserving the quality of the eggs no matter what the type of transport.


All egg storage systems must meet the following requirements:

The first two requirements can be met (for storage periods of three to five months) by: coating eggs with oil or waterglass (sodium silicate); immersing eggs in limewater (calcium hydroxide solution); or putting eggs in dry storage (using such materials as bran, peat dust, soda lime, salt and wood ash). However, all three of the above requirements can only be met by refrigeration, which is the best storage method, if available.

Following below are descriptions of some of the traditional egg storage methods used in the absence of refrigeration. The first two systems rely on evaporative cooling, which is only effective in the hot dry tropics. The hot humid tropics do not allow sufficient evaporation to occur, and thus there is much less of a cooling effect. Where none of these storage systems can be used, there is no way to slow the inevitable drop in egg quality, and the eggs should therefore be transported to the consumer as quickly as possible.

Clay pot

Eggs are placed in a clay pot buried in the ground up to its neck, in a shaded area. The pot is covered tightly so that no water gets into the pot. The ground around the pot is watered, but without leaving puddles of water. Straw or a mat is placed in the pot to cushion the eggs and to keep them above any water that seeps into the container. The eggs are put in the pot as soon as they are collected, and covered with a cloth and damp straw. Due to the evaporative cooling effect, the inside of the pot is often five to six Celsius degrees cooler than the outside air temperature. A variation of this method, used in the Sudan, is to bury an earthenware pot in the ground to half its height. A 7 cm layer of mixed sand and clay is packed around the pot up to its neck, and kept wet by sprinkling water on it. The inside of the pot is lined with grass. The eggs inside are covered with a thin cloth to allow air circulation. Evaporative cooling in Sudan’s hot dry climate often reduces the egg temperature to up to eight-Celsius degrees below that of the air outside. Eggs are turned daily to prevent the yolks touching the shell, which would accelerate the decaying process.

Wet sack cooler

This is another method utilising the evaporative cooling principle. The sack material is kept wet by having a tray of water above the hanging sack, into which the neck-edge of the sack material is dipped, keeping the sack wet. A slightly more sophisticated system uses perforated pipes connected to a water tank. To prevent mould formation, the sacking is pre-soaked in a solution of copper sulphate (CuSO4), using 60 g of crystals in four litres of water.

Oil coating

A thin film of oil on an eggshell fills its pores and reduces evaporation and thus spoilage of the egg contents. Using a wire basket, the eggs are dipped into slightly heated oil, about 11 °C warmer than the eggs. Special odourless, colourless, low viscosity mineral oils can be used. If these are not available, then any light mineral oil or almost any cooking oil that doesn’t easily turn rancid serves the purpose. To reuse the oil, it is cleaned through a filter and heated to 116 °C to sterilize it. Four litres of oil coats about 7,000 eggs. Oiled eggs last for at least three weeks (longer if kept at 10 oC, or less at temperatures above 21 oC). For high temperature storage, eggs should be oiled four to six hours after laying.

Waterglass paste

Waterglass is a paste or ointment of sodium silicate in water. It is rubbed onto the hands and then the egg is rolled between the two waterglass-coated hands to transfer a waterproof coating of waterglass paste to the eggshell.

Waterglass solution

For 100 eggs, a 25-litre pot or jar is used, and 5.3 litres of previously boiled (and then cooled) water are mixed with 0.5 litres of waterglass. The eggs are placed in the pot and covered with the waterglass solution. The pot is covered and kept in a cool, shaded place. The eggs keep for one to six months.

Limewater solution

Limewater is a solution of calcium hydroxide [Ca(OH)2], a mild alkali. The main ingredient is burnt lime (also known as quicklime). The chemical name of this is calcium oxide (CaO). It is also known as choon in Bangladesh, and is a common ingredient of the betel nut mixture chewed by people in many tropical countries. Calcium oxide is made by burning limestone (CaCO3) in a hot fire. Carbon dioxide (CO2) is driven off from the limestone, leaving CaO behind as a white powder. Dissolving this calcium oxide in water makes limewater. The resultant solution of calcium hydroxide is only partly soluble, and the insoluble portion will settle to the bottom of the container.

Six litres of limewater is made by stirring 2.3 kg of calcium oxide into six litres of boiled (then cooled) water. It is allowed to stand overnight so that the insoluble portion settles. The eggs and the clear part of the limewater solution are placed in a pot, covered and kept cool. The eggs last more than a month. In the years prior to 1970, eggs were commonly transported from Bangladesh (formerly East Pakistan) to Pakistan (formerly West Pakistan) on a train journey of about a month, in high temperatures. The eggs were stored in earthenware jars containing limewater and maintained their quality well.

Hot water immersion

Immersion in hot water for carefully controlled lengths of time has a pasteurizing effect, which kills the embryo in fertile eggs, destroys some of the bacteria on the shell and stabilizes the quality of the egg white. The difficulty is to achieve this without coagulating some of the egg white. Equivalent effects are achieved with any of the following temperature-time combinations:


minutes at

49 oC


54 oC


59 oC


60 oC

This method requires special equipment and supervision.

Salt and wet clay or ashes

Eggs are coated in a mixture of salt and wet clay or ashes which allows them to keep for one month. This method has been practised for centuries in China.

Cooked rice and salt

Eggs are covered with a mixture of cooked rice and salt, which allows them to keep for six months. This method has been practised for centuries in China.

Lime, salt, wood ashes and tea

Eggs are covered with a layer of lime, salt and wood ashes mixed with a tea infusion, which allows them to keep for several years. This method has been practised for centuries in China.

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