Chapter 2
Literature review

OVERVIEW

Literature databases used in the search that formed the basis of this review are:

• CAB International (CABI, 1972–1995);

• Agriculture On-line Access (AGRICOLA, 1984–1997);

• Abstracts on Tropical Agriculture and Abstracts on Rural Development in the Tropics (TROPAG & RURAL, 1990–1996);

• International Information System for the Agricultural Sciences and Technology (AGRIS);

• Food Science Technology Abstracts (FSTA, 1969–1997);

• Economist Intelligence Unit (EIU): country reports, sub-Saharan Africa.

Other sources of information were rural poultry workshop and seminar proceedings; technical reports on rural poultry improvement programmes; and theses and dissertations obtained from FAO headquarters, the University of Reading, United Kingdom, the University of Hohenheim, Stuttgart, Germany and Sokoine University of Agriculture, Morogoro, the United Republic of Tanzania.

The volume of literature showed that there is a paucity of data on rural poultry stored in readily accessible systems. Bessei (1988) reported inaccessibility of information on rural poultry production as a major constraint to development. Classification of the citations by publication year and type of publication produced the trend shown in Figure 2.

As shown in Table 2, FAO and other development agencies have increasingly promoted the development of rural poultry through expert consultation meetings, workshops and seminars.

In 1989 the formation of the African Network for Rural Poultry Development (ANRPD) was proposed in an international workshop on rural poultry production in Africa at Ile-Ife, Nigeria, and this proposal was endorsed in 1990 in a seminar on smallholder poultry production, in Thessaloniki, Greece (Table 2). The formation of the network, which has technical and financial backing from FAO, was a major milestone in rural poultry development in Africa. One of the main activities of ANRPD has been the production of a newsletter as a medium for dissemination of information and developments in rural poultry in Africa. Annex 1 shows the international poultry periodicals. Most of these periodicals publish academic and scholarly articles, and some publish trade information for a target group. The ANRDP workshop in Addis Ababa, Ethiopia recommended collation of the grey literature on rural poultry and its publication in mainline scientific journals, publications and books (ANRPD, 1995).

FIGURE 2
Trend of literature on village chicken production systems

Another trend observed in the present review (Figure 3) is that there has been little basic research on various aspects of rural poultry in Africa, except for diseases. As such, most of the citations were general studies of rural poultry development. In the last two decades, socio-economic studies have been incorporated in some programmes, which is possibly a result of the recent introduction of user differentiation and participatory approaches in research and development.

FIGURE 3
Rural poultry topics

VILLAGE CHICKEN PRODUCTION AND HEALTH

Genetic resources

According to Horst (1988), the genetic resource base of the indigenous chickens in the tropics is rich and should form the basis for genetic improvement and diversification to produce a breed adapted to the tropics. Horst (1988) described nine major genes of the indigenous chicken (Table 3) that can be used in genetic improvement programmes. There is little information on the genetic make-up of the indigenous chickens of Africa. However, information collated in the FAO Domestic Animal Diversity Information System (DAD-IS) shows that these genes are prevalent in the local populations across the African countries (Table 4).

Information on the use of the morphological marker genes given in Table 3 for genetic improvement is scanty. Mathur, El-Hammady and Sharara (1989) reported an increase in egg production through incorporating naked neck (Na) genes in a crossbreeding programme of local Fayoumi. Similarly, Horst and Mathur (1992) reported favourable effects of naked neck (Na) and frizzle (F) genes on egg production and egg weight and of the dwarf gene (dw) on feed efficiency of chickens under heat stress.

Apart from the Fayoumi breed developed in Egypt (Hossary and Galal, 1995), there appears to be no record of a tropical adapted breed developed from indigenous chickens in Africa. A programme to produce such a breed in Nigeria failed after introducing a systematic approach of upgrading the breed by replacing the local cocks with Rhode Island Red (RIR) cocks (Oluyemi, Adene and Ladoye, 1979). The RIR cocks in the Nigerian programme succumbed under the poor rural conditions (Adegbola, 1988). Similar observations on genetic improvement programmes based on the introduction of exotic genes in local populations through cockerel exchange, supply of pullets or hatching eggs have been reported in Malawi (Safalaou, 1997), the Niger (Kaiser, 1990) and the United Republic of Tanzania (Katule and Mgheni, 1990). Fayoumi has been introduced in other tropical countries such as Ethiopia (Swan, 1996), the United Republic of Tanzania (Katule, 1989) and Bangladesh (Jensen. 1996).

Currently there is a major global thrust on genetic preservation and biodiversity which is reflected in efforts on development of genome and data banks (National Research Council, 1993; Crawford and Gavora, 1993). These initiatives have come at an opportune time, because continued cross-breeding programmes in rural poultry, which do not consider gene preservation aspects, would lead to erosion of the indigenous germplasm (Bessei, 1989).

Feed resources

Feed resources are a major input in poultry production systems, estimated to account for about 60 percent of total production costs in the commercial poultry sector (Renkema, 1992). In village chicken production systems, it is difficult to estimate the economic and/or physical value of this input because there are no direct methods of estimating the scavenged feed resource which constitutes most of the feed input. Roberts and Gunaratne (1992) asserted that productivity of village chickens is determined by the relationship between the biomass of the chicken population and the scavenging feed resource base. These authors gave two methods for estimating the capacity of the scavenging feed resource using data collected in Sri Lanka. The first method was based on measurement of household refuse and chemical composition of crop contents using the formula:

SFRB = H/P * n(n/n-x),

where

SFRB = scavenging feed resource base;
H = amount of household waste per family per day (kg dry weight);
n = number of families in the community;
x = number of families in the community that do not keep chickens;
P = proportion of the crop content that is household refuse, determined by visual inspection.

The second method suggested by the same authors used production levels of the flock. In this method, the daily consumption of the SFRB was described by the formula

SFRB = ∑E_j /E_s.

where

j = the average number of birds in the family flock obtained in a survey;
E_j = the ME requirement for the daily maintenance and production of each bird per day (kcal/kg dry weight), calculated from production data of growth rate and egg production such as that given by the National Research Council (1984);
E_s = the ME in the scavenging feed (kcal/kg dry weight) from crop content measurement.

Production data of growth rate and egg production are calculated with the National Research Council (1984 formula:

Source: Horst, 1988.

ME per bird daily = W^0.75 (173 - 1.95T) + 5.5DW + 2.07EE,
where

W = body weight (kg);

T = ambient temperature (°C);

DW = change in body weight;

EE = daily egg mass (g).

Using the first method, the scavenging food resource base (SFRB) was estimated to be 203 kg dry weight per family per year, with 23 kg protein and 609 Mcal ME in the Sri Lanka studies. Other studies in Southeast Asia (reviewed by Roberts and Gunaratne, 1992), reported SFRB yields of 475 kg per family per year in Indonesia (Kingston and Creswell, 1982) and 390 kg per family per year in Thailand (Janviriyasopak et al., 1990). With an ME and protein requirement of 11 kcal per hen per day and 11 g protein per hen per day, the protein and energy production levels of SFRB per household estimated in the Southeast Asia studies show that the SFRB energy levels would maintain only two hens. These observations suggest that interventions increasing the village flock size, such as disease control or the introduction of high-yielding cross-breeds, must be accompanied by interventions to increase the SFRB.

In the Sri Lanka studies, the village chicken feed was partitioned into household refuse, 72 percent; grass shoots, 13 percent; small metazoans, 8 percent; and paddy rice, 7 percent. The household refuse was further partitioned into coconut residues, 30 percent; broken rice, 8 percent; and sundries (vegetable trimmings, egg shells, bread, dried fish and scarps), 36 percent. In Ethiopia, no attempt was made to estimate the yields of the household refuse. However, analysis of the crop contents of the chickens showed a high proportion of seed material - 40 percent (Ngesse, 1992).

There has been more research work on qualitative and quantitative characteristics of scavenging feed resources in Asia (Ravindran and Rajaguru, 1985; Roberts, 1991; Gunaratne et al., 1992; Ravindran and Blair, 1993) than in Africa. Ravindran and Blair (1993) gave a detailed description of novel energy and protein resources for scavenging chickens. Similarly, Reddy and Quadratullah (1996) in their discussion on strategy feeding supplementation through locally available resources, provided production and qualitative characteristics of unconventional feeds. The nutritional value of these novel sources was high, e.g. the amino acid content of fly pupae was comparable with that of bone meal and fish meal. In Southeast Asia, some of the unconventional feed resources such as golden snail (Pila leopoldvillensis) have been incorporated in commercial poultry feeds (Ngoupayou, 1993).

In Africa there is little information about research on unconventional feed resources for poultry. Musharaf (1990), reviewing literature on feed resources for small-scale poultry production, included data on tropical crops such as cassava (Manihot utilissima), plantain (Musa sapientum) and yam (Dioscorea rotundata) meals as unconventional energy feed resources. The review also included information on protein sources that are not used conventionally in commercial poultry feeding: palm kernel meal, cashew nut meal and African locust bean seed and pulp.

Source: DAD-IS.

Sonaiya (1993) reported chemical analysis of 20 unconventional foodstuffs, which were mostly by-products of food processing and preparation, such as fermented cassava chaff, ripe plantain, melon pulp, amaranthus seeds, broken cowpea and palm oil sludge. In the study by Sonaiya (1993), 50 percent replacement of a commercial grower ration using a simple ration formulated with palm oil sludge had no significant effect on the growth rate, intake and feed efficiency of commercial cockerels raised in cages. The unconventional ration was also cheaper than grain. Most of the research on these foodstuffs (reviewed by Musharaf, 1990; Sonaiya. 1993) has been based on intensive poultry production units.

Various techniques to produce unconventional feed resources in the tropics have been described, although on a small-scale basis. At village level, Farina, Demey and Hardouin (1991) described a technique used by villagers in Togo to produce eggs and larvae of termites for poultry feeding. Fibrous wastes such as maize, sugar cane and millet stovers were used as substrates and were covered with clay pots or jute sacks on an ant hill. The termites were harvested after three to four weeks and fed to chicks. Similarly, Soukossi (1992) describes a technique of producing maggots in Burkina Faso using maggot culture tanks of 1 m³, filled with water, adding cereal stovers and poultry droppings as substrate. The larvae that developed five to ten days later were harvested and fed to poultry. Forages also form part of the scavenged feed resource. Perez (1997) reported on the use of green-feed cassava and soya forage in a 50:50 ratio to substitute commercial feeds. Baksh (1994) suggested an example of an integrated poultry cropping system where a rotation design is used to produce vegetables and poultry products.

Health and disease control

Major diseases of poultry in Africa that have been predominantly identified in commercial poultry are Newcastle disease (ND), infectious bursal disease (IBD) or Gumboro, Marek disease (MD), fowl typhoid, cholera, mycoplasmosis and coccidiosis (Adene, 1996). However, Chabeuf (1990) argued that the most devastating disease of village chickens in Cameroon is ND, whereas in commercial poultry, coccidiosis, MD and IBD are more prevalent. Research work in other African countries such as Benin (Chrysostome et al., 1995), Burkina Faso(Bourzat and Saunders, 1990), Mauritania (Bell, Kane and Le Jan, 1990) and the United Republic of Tanzania (Yongolo, 1996) supports the argument that ND is the most devastating disease of village chickens.

Other health problems in village chickens are external and internal parasites. A study on ectoparasites of domestic fowls in Nigeria showed that lice, Menacanthus straminen, was the major problem in rural poultry (Zaria et al., 1993). In this Nigerian study, the external parasite problem was associated with season - higher rates of infestation occurred during the rainy season.

A study on the incidence of worms in chicken farms in Nigeria found that the most common species were Ascaridia galli, Prosthogonium spp., Strongyloids avium and Heterakis gallinarum (Tona, 1995). Raillietina spp. and Davainea progglottina occurred only in free-range chickens. In the United Republic of Tanzania, a survey on the prevalence of helminths in village chickens showed a high incidence of Tetrameres americana, Hetarakis gallinarum and species of Hetarakidae, Trichuridae and Raillietinidae (A. Permin, 1996, unpublished).

In view of the above, it is not surprising that Newcastle disease is the most researched disease in village chickens. There is an extensive literature on the epidemiology and control of ND as reviewed by Alexander (1991), Awan (1993) and Yongolo (1996). In 1991, FAO sponsored an international workshop on production and quality control of ND vaccines for rural Africa (Rweyemamu et al., 1991). Recently, there has been increasing concern on control of ND in village chickens, stimulated by the introduction of a thermostable orally administered vaccine (V4) in Southeast Asia, mainly supported by ACIAR (Copland, 1987).

A number of countries have carried out virus isolation and obtained virulent strains (Table 5). Country reports in a symposium on ND vaccines for village chickens indicated that the disease is endemic in Zambia, Malawi, the United Republic of Tanzania, Uganda, Namibia and Botswana. Zimbabwe was reported to be an ND-free country until the first outbreak in 1967, which was controlled after two years. According to Huchzermeyer (1993), the 1967 outbreak was halted by a single vaccination with a killed aluminium hydroxide-absorbed ND vaccine and strict movement control. There were further outbreaks in 1986 and 1994, and recently there have been more sporadic outbreaks, particularly in village chickens.

Alexander (1991) noted that global regulation and control of ND is influenced by the growing multinational poultry trading industry involving poultry products and genetic stock. Furthermore, uncertainties associated with different countries making an open declaration of ND to international agencies such as the International Office of Epizootics (OIE) has limited worldwide control of the disease.

Major factors associated with the transmission of ND in village chickens are exposure to the natural environment, including wild fauna; flocks of various ages and susceptible new hatches (Chabeuf, 1990; Olabode et al., 1992); and contact through either exchange of live chickens and products or movement between households and villages. In an experiment to study transmission of ND in village chickens, Huchzermeyer (1993) ruled out airborne spread of ND in village chickens in the tropics, and asserted that transmission is mainly through contact. Similarly, Martin and Spradbrow (1992) noted that transmission by air is unlikely, because a large number of chickens is necessary to generate sufficiently dense aerosol for such transmission. Therefore, bird-to-bird contact would seem to be the most important mode of transmission in tropical and subtropical production systems.

The recent development and use of thermostable vaccine (NDV4) has created fresh interest for the control of ND in village chickens (Copland, 1987; Spradbrow, 1990; Spradbrow and Samuel, 1991). ln Africa, a number of countries have introduced the vaccine on a trial basis. A major concern has been the identification of appropriate food carriers to introduce the vaccine. Virucidal activity of some grains that reduce the effectiveness of the vaccine have been reported by Rehmani, Spradbrow and West (1995). Jayawardane, de Alwis and Bandara (1990) reported using cooked rice as a carrier for the V4 vaccine. Laboratory virus recovery trials in Zimbabwe demonstrated good virus recovery in pearl millet, sunflower, finger millet and sorghum. In the same trials, barley gave poor results, while crushed and cooked maize exhibited intermediate virus recovery (Department of Veterinary Services, Zimbabwe, unpublished report).

The development of poultry health programmes requires reliable information on the epidemiology of diseases, which is lacking in village chicken production systems (Pandey, 1993). Disease surveillance is further limited by poor infrastructure and communication, as well as inadequate diagnostic facilities. These limitations have resulted in underreporting of disease outbreaks, as observed for ND in the United Republic of Tanzania (Yongolo, 1996). James (1997) cautioned that the animal health status of countries given by the FAO/OIE/WHO Animal Health Yearbook is based on a passive reporting system and that lack of reporting does not necessarily mean the disease is absent. In the same context, the latest OIE report on ND presence showed that only two countries in Africa, South Africa and Swaziland, reported the presence of the disease.

Newcastle disease is probably the only disease identified by farmers in rural areas on the basis of clinical signs. Therefore, ND has acquired specific local names such as Fengle or Enkuref in Ethiopia, Pappa in Mauritania (Bell, Kane and Le Jan, 1990). Kideri, Mdonde, Mdondo, Sotoka ya kuku, Kifwa or Ikula in the United Republic of Tanzania (Yongolo, 1996) and Chibwububu in Zimbabwe (farmers in Zimbabwe, personal communication). Development of appropriate surveillance standards to support farmer identification would enhance an active disease reporting system in village chicken production systems. Use of rapid tests in identifying poultry diseases at farm level has been suggested by various workers as one of the strategies to enhance disease control in rural poultry (Bell, 1991; Verma, 1996). A newly initiated coordinated research programme on increasing farmyard poultry production in Africa initiated by the Joint FAO/ International Atomic Energy Agency (IAEA) Division of Nuclear Techniques in Food and Agriculture, supporting the use of enzyme-linked immunosorbent assay (ELISA) in serological ND screening, will probably enhance disease control (ANRPD, 1997).

Housing

Housing in modern poultry is an important input, accounting for a major component of the initial capital investment. In modern poultry enterprises, the structures are constructed and designed in consideration of bird welfare and efficiency of production (Weaver, 1996; Bhagwat, 1996). Housing in rural poultry is at a rudimentary stage, and field surveys have shown cases where no housing or shelter is provided (Huchzermeyer, 1973; Kuit, Traore and Wilson, 1986; Atunbi and Sonaiya, 1994; Yongolo, 1996). Housing practices for rural poultry in Africa are reported to be influenced by the prevailing farming system, with major differences between the pastoral farming systems and the agro-pastoral or sedentary systems (Kuit, Traore and Wilson, 1985).

Research on the economic efficiency of housing in rural poultry in Africa is scanty. However, published reports suggest that where housing is provided to village chickens, the houses are made with locally available materials such as wood, mud bricks, sugarcane stems, bamboo and cereal stovers (Atunbi and Sonaiya, 1994; Huchzermeyer 1973; Yongolo, 1996). In an evaluation of the economic efficiency of the local materials for housing chickens, Atunbi and Sonaiya (1994) reported that cane cages were cheaper than wooden cages.

VILLAGE CHICKENS IN HOUSEHOLD AND NATIONAL ECONOMIES

The importance of rural poultry in national economies of developing countries and its role in improving the nutritional status and incomes of many small farmers and landless communities has been recognized by various scholars and rural development agencies in the last two decades (FAO, 1982, 1987; Bembridge, 1988; Creevey, 1991; Mokotjo, 1990). However, rural poultry does not rate highly in the mainstream national economies because of the lack of measurable indicators of its contribution to macroeconomic indices such as gross domestic product (GDP). Economic evaluation of livestock at household and national levels is complicated by the multiple functions of livestock in the economy. Moreover, estimating the value of rural poultry is even more difficult than for other livestock because of the lack of reliable production data. Mutizwa-Mangiza and Helmsing (1991), in assessing the contribution of various components of the rural farming system to household subsistence in Zimbabwe, could not estimate that for the livestock production subsystem, although the study concluded that diversification, including keeping of livestock, increased household food security. Similarly, in the Gambia, a national agricultural survey had to omit the poultry component owing to lack of measurable indicators for this sector (Y. Jalo, personal communication).

The rural poultry population in most African countries accounts for more than 60 percent of the total national poultry population, which has been accorded an asset value of US$5 750 million (Sonaiya, 1990a). In Burkina Faso, Ouandaogo (1990) reported that the 25 million rural poultry produce 15 000 tonnes of meat, out of which 5 000 tonnes are exported at a value of US$19.5 million, mainly to Cote d'lvoire. Forssido (1986) estimated that village chickens provide 12 kg of poultry meat per inhabitant per year, whereas cattle provide 5.3 kg per inhabitant.

Village chickens are more widely distributed in rural Africa than the other livestock species. In the United Republic of Tanzania, a survey of 600 households in 20 villages showed that chickens were the only form of livestock found in most households (Collier et al., 1986). Similar observations have been reported in the Niger (Abdou and Bell, 1992), in Ghana (van Veluw, 1987) and in Mali (Kuit, Traore and Wilson, 1986).

Surveys in some African countries have reported that the main function of village chickens from the farmer's perspective is the provision of meat and eggs for home consumption [Mali (Kuit, Traore and Wilson, 1986); Ghana (van Veluw, 1987); the United Republic of Tanzania (Kabatange and Katule, 1989); South Africa (Cairns and Lea, 1990); the Gambia (Andrews, 1990); the Niger (Abdou and Bell, 1992) and Côte d'Ivoire (Diambra, 1990)]. Apart from increased quantitative production of animal protein in rural households, chicken meat and eggs provide protein of a higher biological value than that of red meat (Norman, 1973). Chicken meat and eggs are reported to complement staple diets of rural Africa due to the higher nutrient concentration (Table 6). Small poultry production units of 12 laying hens per unit have reported an increase in the consumption of animal protein and reduced incidence of malnutrition in resource-poor households of South Africa (MacGregor and Abrams, 1996).

Source: FAO, 1997c.

Rural poultry is also an important element in diversifying agricultural production and increasing household food security. The village chickens provide readily harvestable animal protein to rural households, and in some parts of Africa are raised to meet the obligation of hospitality to honoured guests (Figure 4). Chale and Carloni (1982) reviewed the attributes of chicken meat and eggs in rural areas. Egg dishes and chicken meat cook faster than pulses and red meat, and therefore use less fuelwood. In the same review, citing poultry projects in Asia and Africa, the authors highlighted the importance of chickens as a diversification component in rural farming systems, particularly for women. Income accrued from the sale of eggs in a women's project in the Sudan was used to purchase household consumable goods, thus increasing household welfare. Gittinger, Leslie and Hoisington (1987), in a survey on food production by women and its impact on food security, found that rural households that had cropping as their only source of food production were more food insecure than households that had livestock, including poultry. Similarly, Bembridge (1988), assessing the impact of a maize extension programme based on a survey of farmers' needs. indicated that diversification including poultry would be beneficial to women.

The advantages of household poultry in improving household food security and increasing household welfare have been reported in other regions. In India, Desai (1996) reported successful rural poultry projects involving women, which led to increased production and empowering of women through provision of training and credit. Similar projects have been reported in Thailand and Honduras (FAO, 1994; Bradley, 1996), as well as Bangladesh (Saleque and Mustafa, 1996). The importance of organizational and capacity building in enhancing increased rural women's poultry production featured highly in the projects in Asia and Latin America. The recent developments in the importance of poultry in household food security, especially for the poorer members of the community, including increased distribution of resources through involvement of women, have been appreciated globally. Household poultry has been included in the FAO Special Programme for Food Security (SPFS) (FAO, 1997b), endorsed in the Rome Declaration and World Food Summit Plan of Action in November 1996 (FAO, 1997a).

The participation of women in rural poultry improvement programmes contributes to human development both by increasing access for rural women to income and knowledge, and by increasing production efficiency (Aboul-Ella, 1992; Bradley, 1992; Scola, 1992). In a recent review, Bradley (1996) suggested that increased contribution of poultry production in national economies through the involvement of women will be attained primarily through explicit incorporation of gender issues in such programmes, thus involving rural women directly in rural development. Similarly, Kitalyi (1996) suggested that transformation of the village chicken production systems of Africa into economically viable enterprises would require better understanding of the socio-economic aspects of the production system.

FIGURE 4
Village chickens provide readily harvestable animal protein to rural households