The aim of this paper is to provide up-to-date information about the status of broiler production in Flanders (the northern region of Belgium) and the opinion of Flemish broiler producers on animal welfare. Our review revealed that intensification of Flemish broiler production has continued, as characterised by a decreasing number of production plants with up-scaled production. Results of a quantitative survey of Flemish broiler producers showed that the typical broiler house is 21 years old and houses 35,000 mixed-sex Ross broilers indoors on wood shavings or straw. The commonly-used modal management implies thinning one-fifth of the flock at the age of 35 days. The remaining broilers are slaughtered when they are 42 days old and weigh an average of 2.4 kg. The median unassisted mortality rate is 2% and another 0.5% are culled. Further scaling-up of production units is not viewed favourably by producers, particularly as related to consumer acceptance. Producers state they place great importance on animal welfare and do not agree that broiler welfare is poor. A small minority of producers plan to invest in improving broiler welfare in the near future. They see few advantages in paying more attention to broiler welfare or providing outdoor access to improve their public image and consumer acceptance. Producers define animal welfare mainly in terms of good health, feeding and housing and consider aspects that relate to the birds’ ability to express appropriate behaviour as less important. We discuss how this concept of ‘animal welfare’ corresponds to that reported by other people with farming backgrounds. Unfortunately this belief contradicts the perception of citizens and consumers and the assumptions underlying the proposed European standards for monitoring farm animal welfare as developed by the Welfare Quality® consortium.

The use of light emitting diodes (LEDs) as a source of monochromatic light to determine its impact on immunity and meat quality in poultry is investigated in the current review. The use of LEDs in poultry housing is preferred over other conventional light sources. LEDs emitting blue, green and yellow wavelength have been shown to improve the immunity and meat quality responses in broilers. Blue and green light help to promote greater antibody production and immune function, compared to red light. Keeping birds under yellow and green-blue mixed lighting has resulted in softer breast and drumstick muscles while white light improved lean meat and amino acid content of meat. From the available research it can be inferred that birds perform better in terms of meat quality and immunity if reared under the environment of monochromatic light produced by LED for cost-effective and advanced poultry production.

The aim of this review was to analyse the available literature on the effects of the use of microelements and their chelated forms on performance parameters of poultry as well as the cholesterol content in the tissues of broiler chickens. Published research has indicated that the significantly lower levels of organic minerals had a positive influence on the production performance of meat poultry and improved the production performance of laying hens and their heavy line hybrid parents. This has major impacts not only in terms of more efficient utilisation of chelated minerals in poultry diets, but also for less excretion of unused inorganic minerals into the environment, which is a major problem in many countries.

Sub-clinical necrotic enteritis (NE) is a major economic cost to the broiler production industry due to poor growth and feed conversion efficiency of broiler chicken flocks, higher condemnation of livers or rarely the whole carcasses at the slaughter house and an increased risk of microbial contamination of poultry meat. Sub-clinical NE is a multifactorial disease although Clostridium perfringens plays a major role in its pathogenesis. Its diagnosis and confirmation are quite different from those of general infectious diseases. Disease confirmation is from the presence of necrotic or ulcerative lesions on the small intestinal mucosa with identifiable aggregates of pathogenic C. perfringens. C. perfringens numbers in the small intestinal digesta or the mucosal scrapings are not correlated with disease severity, whereas counts above 106 cfu/g in the caecal contents indicate an increased probability of NE-specific gut lesions. Not only does the presence and counts of C. perfringens strains capable of producing related toxins affect the incidence of the disease but also a number of predisposing factors are important in the aetiology of NE. The major factors that predispose growing chickens to sub-clinical NE are diet variables, diseases that cause mucosal damage of the intestine and environmental factors that either alter the development of gut associated lymphoid tissue or change litter quality within the production house. Dietary variables may be a major cause of variation in sub-clinical NE in commercial broiler production; differences in polysaccharides, lipids, protein sources, protein digestibility and the presence of antinutritive factors have been identified as variables affecting the incidence of the disease.

Hydropericardium syndrome (HPS) is a fatal disease of broiler chickens causing high mortality and heavy economic losses in various countries. More than 100 million birds have been affected by this destructive disease in less than two years worldwide. As it is a viral disease, the only solution is to vaccinate chickens. Different types of vaccines are being used against this disease in different areas of the world. Liver organ inactivated vaccines are more extensively used to control the disease initially. These vaccines have many drawbacks regarding their dose, un-predictable immune response and secondary bacterial infections. Following this, oil adjuvant vaccine was used to control the disease, however the handling stress and the formation of granuloma at the site of injection remains a problem. Consequently there is a need for cell culture adapted and attenuated vaccines, which can be administered through oral routes. A chicken embryo-adapted inactivated vaccine has shown good results but requires a continuous supply of specific, pathogen-free chicken embryos and a continuous life killing process. The continuous cell lines are a more promising solution for the production of cell culture-adapted and attenuated vaccines, which are safer, more economical and easy to administer. The following review discusses the development of modern HPS vaccines.

Poultry red mite (Dermanyssus gallinae), the haematophagous pest of egg laying hens, is an important problem in poultry production in many parts of the world. Control has typically relied on synthetic acaricides in spite of advancements in immunological, biotechnological and genetic approaches. However, the repeated long term use of these compounds has resulted in the development of drug resistant populations of poultry mites, therefore, the availability of effective acaricides is diminishing rapidly. Due to this, there is need for the continuous availability of new chemical acaricides to replace the older types, however the development and registration of new acaricides is a long expensive process, therefore, preserving and maintaining the effectiveness of available acaricides is essential.

This review has two parts; the first is to provide the basic understanding of acaricide resistance in D. gallinae while the second part provides more detailed knowledge about the management of resistance to preserve the efficacy of available acaricides.

This review covers the egg production models used in poultry. Similarities and discrepancies among the models are illustrated using a real data obtained from a layer breeder flock. Egg laying in poultry begins at sexual maturity and quickly reaches peak production, and then declines with hen age. For many years, egg production studies have been carried out for the purpose of modelling. Some of the functions were developed for this purpose, such as nonlinear regression equations (Gamma, McNally, McMillan, Adams-Bell, Compartmental, Modified Compartmental, logistic-curvilinear, Gloor, Lokhorst, Narushin-Takma) and some Multiphasic (Segmented Polynomial, Persistency, Individual). Almost all of these functions have been developed to allow modelling on the basis of flock averages. Most models having empirical structure and a small number of parameters are considered biologically meaningful. New models are currently required to be useful for both individual egg yields and to contain biologically relevant parameters.

During chick embryo development, there exists an antioxidant-oxidant balance in the tissues, which supports normal embryonic development and post-hatch chick viability. This balance is maintained by natural antioxidants including vitamins A, E, C and carotenoids, glutathione peroxidase (GSH-PX), catalase (CAT) and superoxide dismutase (SOD). Chick viability is an important factor in determining post-hatch health and profitability. Factors that interrupt growth and development during the embryonic period affect the overall performance and health during the post-hatch period. During the 21-day incubation period for chickens, antioxidant defence systems protect the embryo against the lipid peroxidation (LPO) derived from undesirable conditions. The purpose of this review is to explain the antioxidant mechanisms that contribute to chick embryo development resulting in a healthy hatchling.

Newcastle Disease (ND) is regarded as one of the major diseases of poultry because of the devastating losses that the virulent form of the ND virus can impose on both commercial and domestic chickens. However, the disease can be controlled through the administration of effective vaccines. Almost all the commercially available ND vaccines require refrigeration and begin to deteriorate rapidly after 1-2 hours if left at room temperature (around 25°C). Subsequently, because maintaining an adequate supply of refrigerated facilities may be a difficult task in many countries with unreliable electrical supplies, the development and large scale production of an effective thermostable ND vaccine seems imperative to support the poultry industry. Such vaccines should be resilient to damage associated with either very cold or hot environments so there are no concerns about the viability of the vaccine in response to temperatures fluctuations that can occur in extreme environments when the difference in temperature during cold and warm seasons can vary greatly. In the following review paper, the development of such a vaccine is discussed, including molecular characterisation, organ tropism of vaccine strains, production, as well as administration methods and their efficacy. It addition, the potential payback has been calculated alongside opportunities provided by removing vaccines from cold chain storage.

Similar to omega-3 eggs, chicken meat has great potential to become a functional food for humans. In India, chicken meat is preferred due to its perceived health benefits and affordability. The balance between omega 3 and 6 fatty acids is crucial for its usefulness in animals. At present commercial chicken meat has low omega-3 fatty acid content and higher omega-6 fatty acid content. Published research shows that it is possible to modify the lipid profile of commercial chickens by manipulating the broiler diet. The modern human diet is deficient in n-3 FAs, which has been linked to the increase in several degenerative diseases such as cardiovascular disease, diabetes, arthritis, cancer and mental illness. Therefore omega-3 chicken meat may be an effective means of increasing n-3 FA in the human diet. There are several problems associated with the commercial production of omega-3 chicken meat related to the choice of source of fatty acids in the feed, cost of production, consumer acceptability and stability of the chicken meat that need to be tackled. The present article briefly reviews the studies carried out in this respect, the possible impact of omega-3 chicken meat production on the poultry industry, and on human health.

Deep pectoral myopathy (DPM) of musculus pectoralis minor is an anomaly observed in gallinaceous poultry. To date its cases have been reported in adult pedigree turkeys and hens and in recent years also in broiler chickens. This degeneration is manifested in an abnormal appearance of breast muscles, with changes in colour from pink to green, as well as changes in the texture of the muscle tissue. The anomaly is found most frequently in genetic lines of chickens characterised by dynamic weight increment in the rearing period as well as a considerable increase in the proportion of pectoral muscles. The mechanism for the development of myopathy is already well known. It is related with ischemic necrosis initiated by rapid physical activity of birds, which mobilises pectoral muscles, normally relatively inactive in modern intensive animal management systems. Absence of symptoms manifested in vivo results in a situation when muscles affected by myopathy are identified only during carcass dissection. An increasing number of cases of this anomaly, as well as the fact that necrotic lesions affect valuable carcass elements make this problem one of great importance for chicken growers and abattoirs and poultry processing plants. In recent years DPM cases have been reported with increasing frequency in the USA, Italy, Greece and Bulgaria in commercial genetic lines. In Poland, a number of DPM cases have been recorded in large populations in flocks of five to seven week old chickens from 0.02% up to 1.9%. Risk factors for the occurrence of DPM on farms have been analysed, and are considered mainly due to intensive wing flapping. Identification of these factors may result in better farm management and constitute the basis for the DPM prevention system. A solution to this problem is not available currently.

Glycine is a multi-tasking amino acid involved in multiple metabolic and functional systems, including sulphur amino acids, proteins and immunoglobulins syntheses, blood haem and bile production. Glycine is also capable of eliciting responses at whole animal level, such as those promoting gut and immune health, animal welfare as well as feed/food safety. Empirical evidence shows that glycine supplementation can arrest systemic inflammation via deletion of cytokine production. Some investigators have corrected gut wall damage in challenge studies via gastric infusion of glycine. Efficacy data further document that glycine aids bone accretion in broilers fed reduced protein diets. Given these glycine bioefficacies, particularly in broilers, its nutrition needs to be critically assessed in the light of modern paradigms of animal welfare, feed-food safety, efficiency, reduced antibiotic application, and eco-sustainability. Such efforts should concentrate on precise estimation of inevitable ileal flow of glycine so as to generate a database on the digestible glycine levels in feedstuffs. Only this can provide for proper control of feed glycine density.

Controversies on dietary glycine optimum for broilers also need to be addressed, as this has significant ramifications for raw materials selection and eco-sustainability. Based on a meta-analysis of published reports a range of 1.91-2.27% of total glycine+serine is recommended in young broilers diets, depending on production goals. But clarity is still needed on how this may be modified by practical stress conditions. The efficacy of copious supplementation of crystalline glycine to promote key parameters of poultry health and zootechnical performance under different rearing conditions still needs to be resolved.

Infectious bronchitis virus (IBV) is one of the foremost causes of economic loss within the poultry industry. IBV is a commonly occurring, economically significant pathogen of commercial chicken. Economic consequences to the poultry industry comprise mortality, growth retardation and high condemnation rates in meat-type birds. In addition, decreased egg production, reduced internal and external egg quality, and reduced hatchability have been documented in layers and breeders affecting the performance of both meat-type and egg-laying birds. Apart from this some nephro-pathogenic strains cause kidney damage. Secondary pathogens can complicate the disease resulting in increased morbidity and mortality. Being a single stranded RNA virus, IBV has an enormous capacity to change both by spontaneous mutation and by genetic recombination resulting into the emergence of new variants. Since the first isolation of virus in 1937, it has been found almost all over the world. In addition, most countries are now known to have their own indigenous IBV variants. Despite the use of currently available live and inactivated vaccines, one of the most important difficulties to control IB is related to emergence of variant strains. The following paper reviews the current status of research into IBV.

The nutritional benefits of consuming long chain ω-3 polyunsaturated fatty acids (PUFA), which are found predominantly in linseed for example, are well known. The consumption of poultry meat has increased in consumption by 80% in the last three decades. The best method of increasing long chain ω-3 PUFA consumption would be to increase the long chain ω-3 PUFA content in the edible tissues of poultry aimed for human diets. It has been shown that heart and blood vessel diseases, as well as the occurrence of atherosclerosis are a direct consequence of consuming products of animal origin in human nutrition which contain a high content of lipids rich in saturated fatty acids (SFA), which are the main causes of these diseases. For these reasons healthy foods enriched in PUFAs, particularly ω-3 fatty acids, have gained high importance because of their beneficial effects on human health.

Apart from the importance of being able to predict chicken carcass conformation it is also necessary to calculate the required level of fatty acids in the chicken diet that are incorporated into the edible tissues. Regression analysis is most often used for this prediction. The goal in regression analysis is to create a mathematical model that can be used to predict the values of a dependent variable based upon the values of an independent variable. The aim of this paper is to show possible solutions for broiler edible tissue enrichment with ω-3 fatty acids from linseed, and to give possible solutions to the inclusion level of fatty acids in the diets using regression analyses.

Ammonia (NH3) emissions from poultry farming operations have become a crucial concern due to their potential adverse effects on performance, birds and human health, and the environment. Due to genetic improvements, current commercial poultry require high quality balanced nutrition to maintain their rapid growth and production. Amino acids are components of protein nutrition that greatly influence the growth of the birds, and methionine is the first limiting essential amino acid in the high protein diets of poultry. However, excess or misuse of amino acid supplementation to poultry diets increases nitrogen (N) excretion and emissions to the environment. Currently, there are limited numbers of research publications regarding NH3 emissions from poultry manure, and few of them address manure enhancement by microbial nitrification. Therefore, the aim of this review is to evaluate the potential of soil nitrifying bacteria to reduce NH3 volatilisation and enhance N retention in poultry manure. This review presents the current status of knowledge regarding soil nitrifying bacteria, NH3 nitrification, and summarises the strategies to enhance microbial nitrification of poultry manure, and the environmental ramifications when using different techniques to control NH3 emissions. In spite of the fact that there are few research studies on reducing NH3 volatilisation through nitrification, it has been concluded that nitrification would be a sustainable method for mitigating N excretion and NH3 emission from poultry; however, further research is needed to identify the proper nitrifying bacteria to enhance microbial nitrification.

To ensure health and reproductive performance, broiler breeders are feed restricted during the rearing period and, to a lesser extent, during the production period. Although restricted feeding improves health and bird welfare, on the other hand the birds are chronically hungry and suffer from frustration of feeding motivation, which has a negative effect on bird welfare. The aim of the current paper is to give an overview of the role of feed (nutritional aspects as well as feeding management) as a possible tool to improve broiler breeder welfare. Possible strategies discussed are 1) dietary dilution, by reducing the energy content and/or increasing the NSP content, by adding soluble or insoluble fibres to the diet; 2) adding appetite suppressants (e.g. calcium propionate) to the diet; 3) changing feeding management (e.g., scattering feed in the litter). Some of these strategies, i.e. dietary dilution or adding appetite suppressants, positively affect behavioural patterns of the birds, by reducing stereotypic pecking and eating motivation, and increasing the time spent sitting. Appetite suppressants have however been criticised for causing birds to feel ill. These behavioural changes, however, can only be considered as indirect parameters of improved bird welfare and there is still a need for a reliable indicator of hunger. It is clear that nutritional strategies can be helpful in reducing hunger stress in broiler breeders. Nutrition, however, cannot fully solve the broiler breeder paradox. The main reason for this paradox is related to breeding goals that are focussed on improving feed conversion and increasing breast meat percentage. Future genetic selection should aim at uncoupling the link between (re)production and welfare or reducing the conflict between these outcomes.

Alternative laying hen rearing systems have been rapidly introduced into poultry production in an effort to harmonise poultry health and welfare with consumer, producer, industry and environmental demands. They are an integral part of modern egg production. Husbandry systems for keeping laying hens have an impact on, inter alia, the chemical composition of eggs. The subject matter of this study is a comparative review of the results obtained by different authors on the effect of rearing system on chemical composition (proteins, lipids, cholesterol, vitamins and fatty acids content) and hygienic conditions of eggs from different rearing systems of laying hens. Eggs from these laying hen rearing systems have been proven by a large body of literature data to have better nutritional properties. Moreover, the results analysed also indicate differences within rearing systems. Rearing systems also have an influence on hygienic and microbiological quality of eggs. In view of the above, this comparable overview of the literature on the use of different rearing systems in table egg production can serve as a tool in determining the future direction of research as well as an indicator of its practical application.

This review is a first attempt to give a comprehensive historical account on the evolution of the Maltese Black chicken breed. The initiative consolidates available information to propose hypothesis on the origins of the breed, and to develop a comprehensive breed standard in conformity with the format of the American Breed Standard. The Maltese Black was established in 1950 as a rustic, dual purpose breed capable of producing adequate egg and chicken for consumption. In the 1960's, it was replaced with commercially available stock, marginalising the breed and restricting its existence to small dispersed populations. An initial attempt to have an in-situ conservation of the Maltese Black started in 1998 with a small flock of about 400 chickens that were later relocated to the Agricultural Research and Development Centre in Malta with the intention of maintaining a nucleus flock as a measure for a long term ex-situ conservation strategy. A recent survey highlights that the present population has drifted significantly away from standards first published in 1950. In efforts to consolidate the breed standard definition of the Maltese Black, the breed standards of related Mediterranean breeds, as confirmed by molecular markers, were consulted to translate and address the missing gaps in the previous breed standards. The updated breed standard presented will act as the bench mark against which all future breeding and selection programs are compared.

The importance of scavenging chicken production in the national economy of developing nations of Africa and its role in improving the nutritional status and income of many smallholder farmers has been recognised by several scholars and policy makers the world around. Scavenging chicken production is a profitable enterprise that contributes to poverty reduction especially among the resource challenged rural communities in most parts of the developing world. It is particularly suitable to smallholder farmers and landless peasants due to low capital investment, high cost efficiency, flexible production systems and low production risks. It has also a symbolic significance within the context of socio-cultural as well as religious functions and economically empowers the rural youth and women. Chicken meat and eggs provide a readily available, high-quality source of proteins, vitamins and micronutrients which are particularly essential for children, pregnant women and nursing mothers. Moreover, meat and egg from scavenging chicken present one of the most environmentally efficient animal protein production systems.

The major challenges of the scavenging chicken production in Africa include high chicken mortality due to predation and regular outbreaks of diseases notably Newcastle disease; imbalanced nutrition due to poor quality and quantity of feed materials; lack of organised marketing system and low performance related genetic potentials. The growing demand for scavenging chicken products in urban areas, identification and promotion of ethno-veterinary medicines, developing locally made and appropriate housing structures, selection among the scavenging chickens, organising farmers to increase bargaining power and shortening the marketing chain are considered as the major opportunities for the improvement of scavenging chicken production in Africa. The significance of indigenous chickens for farmers in African countries combined with many consumers’ preference for their eggs and meat suggests that these genetic resources are promising options for food security in the rural communities.

Since January 2006, the use of antibiotics for domestic animals as feed additives has been banned within the European Union, influenced by the consumers’ demands for products free of antimicrobial residues. As an alternative, probiotics in animal nutrition have attracted attention for their potential roles as growth promoters as well as antibiotics. Recently, much research data has been gathered and suggests a potential role for probiotics from fungi as natural growth promoters in broiler nutrition. One such fungi, Aspergillus awamori, has been shown to improve the growth performance and meat quality of broiler chickens. This review examines the current scientific data on the use of A. awamori as a probiotic in broiler nutrition. From the available literature, it can be concluded that A. awamori may provide an effective alternative to antibiotics in the production of broilers.