Severe disease outbreaks of erysipelas in poultry flocks are caused by infection with the bacterium Erysipelothrix rhusiopathiae. This disease occurs in a wide range of poultry, including turkey, broiler chicken, hen, goose, and pheasant flocks. Erysipelas usually follows an acute course in birds, in the form of sepsis. Infections with E. rhusiopathiae occur through damaged skin or mucous membranes. The symptoms that occur just before death include unsteady locomotion and a lack of coordinated movement. A chronic form of bacterial infection primarily occurs in turkeys that have been vaccinated against erysipelas, and, in addition to affecting the joints, endocarditis can occur. Usually, carcasses are in good condition and correctly muscled, although ecchymosis might be visible in subcutaneous fat and thigh muscles, while internal organs become enlarged, such as the liver, spleen and kidneys. Histopathological tests indicate major vascular changes in the parenchymatous organs. Points of necrosis related to the infarctions of the large vessels are rarely observed, whereas spilled degenerative changes of parenchymatous organs are more likely to be observed. Turkeys are the only species of poultry for which vaccines against erysipelas have been registered; however, this vaccination is also effective for other poultry. E. rhusiopathiae is mainly sensitive to penicillin, but also responds to cephalosporins, tetracyclines, quinolines, clindamycin, erythromycin, and piperacillin.

Egg storage is a common and important practice in the poultry industry. Knowledge of the effects of storage on the egg, the embryo and incubation yield is important for planning incubation by hatcheries. Recommendations for storage environmental conditions depend mainly on the breeder age and storage time. Storage from seven days or more alters the characteristics of albumen, reduces incubation yield, increases incubation period and can damage embryonic development. When working with long storage periods, the adoption of management practices such as storing the egg with the thin tip down, egg turning during storage and pre-storage incubation should be considered to reduce the negative effects on the incubation yield.

The metabolisable energy of corn can vary by more than 400 kcal/kg in poultry. Chemical, rather than physical kernel characteristics may be more accurate for predicting nutrient and energy availability. Factors that affect variability include genetics, agronomic conditions, proximate composition, pre- and post-harvest processing variables, and the presence of anti-nutritional factors. Variation in the nutritional value of corn may be better identified when the relationship between protein and starch are considered rather than by total content or predicted digestibility values alone. Recently, the use of near-infrared reflectance spectroscopy has made rapid valuation of corn based on chemical kernel characteristics a possibility. Prediction equations may be useful for formulating diets to more closely approximate actual metabolisable energy content for poultry.

Avian intestinal spirochaetosis (AIS) is primarily a disease of layer and broiler breeder chickens exhibited by delayed and/or reduced egg production, increased mortality, weight loss, and chronic diarrhoea. This disease is of concern to the egg industry because of the economic impact of reduced production and down grading of eggs due to faecal-stained shells. Avian intestinal spirochaetosis is caused by pathogenic Brachyspira spp. This review summarises the species of Brachyspira that have been associated with AIS and provides an overview of epidemiological studies that have investigated prevalence, risk factors, and preventive measures for Brachyspira spp.

Meat colour and tenderness are considered as two of the most important quality attributes influencing consumer's purchasing and repurchasing decisions respectively. This review discusses the importance of poultry meat quality with reference to texture/tenderness. The manuscript includes different factors affecting poultry meat texture, methods for improving tenderness, ultra structural changes, and comparison of up-to-date tenderisation methodologies available in the literature are discussed. The tenderising efficacy, advantages and disadvantages of various physical, chemical, enzymatic characteristics and their synergistic effects in poultry meat is narrated. This review provides comprehensive information for poultry processors, retailers and consumers and gives an overall view to researchers.

One of the environmental challenges that the poultry industry has faced is manure utilisation and/or disposal. Poultry manure and its nitrogenous compounds can be a potential pollutant causing eutrophication, nitrate or nitrite contamination of water, ammonia volatilisation, and acid deposition in the air. Therefore, reducing nitrogen excretion and emissions in poultry manure is important to maintain a clean environment. Proper nutrition is an important first step to optimise performance and growth in animals as well as to reduce the negative impacts on the environment. Amino acids are components of protein nutrition that greatly influence animal growth. However, excess or insufficient amino acid supplementation in diets increases nitrogen excretion and emissions. One way to reduce this is to prevent uricase activity in the microflora in poultry manure. Egg yolk antibodies are economic alternatives for administering in feed to poultry. Supplementation of feed grade antibodies into poultry diets can be a potential approach to minimise bacterial uricase activity and reduce ammonia emissions from poultry manure. In order to use this dietary strategy effectively, a well-balanced feed formulation and a more practical way of delivering the antibodies in feeds remains to be developed.

High ambient temperatures in tropical and subtropical regions adversely affect the growth and egg productive performance of both broiler and laying chickens. Relative humidity and ventilation rate influences bird's performance, particularly when they are reared in open sided poultry houses. Genetic approaches that aid in reducing or altering the extent of plumage cover has, as a result, been adopted in many hot regions. Fortunately, there are some major and marker genes can reduce the deleterious effects of heat stress, naked neck (Na) and frizzle (F) genes being the most notable ones. The bulk of relevant literature has shown that their favourable effects on growth and laying performance are well established. Therefore, the naked neck and frizzle genes can be a viable alternative for broiler and layer production particularly, in the tropical countries where summer temperatures are very high.

The zootechnical performances of broilers at the end of the rearing period depend in part on the quality of day-old chicks at placement. The quality of day-old chicks is highly affected by the incubation conditions, by hatch time (which determines the time spent in the hatcher under high temperature and humidity), and by the handling of chicks after hatch. This article first presents an overview of the most relevant pre-incubation factors that affect chick quality: egg size, egg weight, quality of eggs, sex of embryos, age of breeders, and conditions and duration of egg storage. It then reviews the most important incubation factors that affect hatch time, hatchability and hatch window (temperature, humidity, turning, ventilation and concentration of gases). Finally, the effect of early post-hatch handling (including processing and especially transportation of chicks) as a possible source of stress influencing the quality of chicks at placement is discussed.

Campylobacteriosis is the most frequent zoonotic disease in humans worldwide. Poultry meat contaminated by Campylobacter jejuni (C. jejuni) is an important source of this enteric zoonosis. Broiler chickens are the common natural host for this pathogen and infected birds carry a very high Campylobacter load in their gastrointestinal tract. Therefore, intervention at the farm level by reducing pathogen colonisation should be taken into consideration in any control policy. In addition, hygienic measures at the farm and control measures during carcass processing can reduce Campylobacter numbers on the retail product. It is important to differentiate between prevention and colonisation-reducing measures, which intervene at a different stage of the infection process. Several approaches have been conducted to reduce the number of Campylobacter in poultry, such as vaccination, passive immunisation, bacteriophages, bacteriocins, organic acids or their derivatives and medium chain of fatty acids, all with varying degrees of success. Nonetheless, to date there is no reliable and practical intervention measure available to reduce colonisation of the broiler gut with Campylobacter. A possible way to reduce Campylobacter contamination in poultry is to develop new strategies at the primary production level. As a consequence, it has become necessary to develop alternatives such as beneficial microorganisms (probiotics). The use of probiotics can help to improve the natural defence of animals against pathogenic bacteria and is an effective approach for livestock to reduce bacterial contamination. This review summarises current on-farm control options to reduce the prevalence and colonisation of Campylobacter in poultry. The interaction between poultry welfare and Campylobacter colonisation is also discussed.

The quality of poultry feed is an important precondition to achieve optimal production results, and the preservation of the health status of animals, especially in intensive livestock production, hence it is necessary to control both raw materials and finished feed mixtures. The presence of fungi (moulds) in food for animals is a natural phenomenon, not an exception. Sources of contamination of poultry feed with fungi and resulting mycotoxins vary, starting with raw materials (e.g. corn as the most common component) during harvest and transport, during storage of raw materials and finished products, as well as in the production process and manipulation of poultry feed. Mineral adsorbents are increasingly used in poultry production, especially in the nutrition of various types and categories of poultry, to control fungal contamination. Using different mineral adsorbents in poultry nutrition can prevent the losses due to mycotoxicosis. It can also prevent appearance of toxic residues in poultry products, improve production and reproductive ability of birds, and contribute to improving the quality of poultry products. In addition, the use of mineral adsorbents in poultry feeds has application in neutralising the harmful effects of mycotoxins in buildings where poultry is reared.

The variability of phosphorus (P) availability in poultry feeds is large, primarily caused by differences in the contents of phytate and intrinsic or exogenous phytase and by differences between non-phytate sources of P. Attempts to consider this variability in feed formulations has led to the development of different approaches to determine P availability. In the past seventy years, different response criteria and descriptive terms for available P have been used. In this review, response criteria that are often used will be described, including their development over time. Focus is be given to growing poultry and to quantitative approaches based on P retention and precaecal digestibility, relative bioavailability based on bone data, and in vitro solubility tests. In conclusion, precaecal digestibility and retention are the most appropriate criteria for evaluating P sources in poultry. The use of blood inorganic phosphorus (Pi) concentrations and performance data is discouraged for the purpose of evaluation. Bone response data can provide relative availability values for P sources. More research is needed to explore whether P retention data can be re-calculated from existing bone response data. Improvements in in vitro approaches for estimating P availability are suggested.

The requirements of different electrolytes (sodium, potassium and chloride), dietary electrolyte balance (DEB) and salt source in broilers have considerably changed in recent times. The increasing level of sodium (Na), potassium (K) and DEB are associated with higher pH (i.e. alkalosis) while lower levels of chloride (Cl) and DEB are linked with a lower pH (i.e. acidosis). A narrow range of DEB (150-250 mEq/kg) is recommended to overcome the variations in acid base homeostasis and normal blood chemistry especially in summer conditions. The supplementation of suitable salts like NaHCO3 and KCl are proven to be beneficial to sustain viability of various biochemical processes. The cations usually alleviate whereas anions exacerbate the lysine:arginine antagonism. In most cases, the electrolytes and their balance (DEB) are considered ineffective in order to influence carcass and related traits; however, the supplementation of their respective salts, particularly NaHCO3 and KCl under heat stress, showed contrary but potentially useful results. The role of electrolytes in combination with coccidiostats is still ambiguous; however, the level of both entities (electrolytes and coccidiostats) should be kept low and studied in detail for mutual compatibility. The inclusion level of electrolytes from various salt sources changes whenever there is change in coccidiostat and environmental condition. Keeping in mind environmental constraints, it is recommended to use the lowest dosage of NaHCO3/ NaCl alongside ionophores. Consequently, it is recommended to supplement electrolytes through a combination of NaHCO3 and KCl, and maintaining dietary electrolyte balance (150-250 mEq/kg) is mandatory to exploit improved physiological responses of broilers for maximum growth response.

This review paper delineates how vitamin D3 and its metabolites produce beneficial effects on the performance of both broiler and egg laying chickens. This review provides information on the evaluation of cholecalciferol sources, metabolites, requirements for cholecalciferol in birds, its effect on hatchability of fertile eggs and its impact on immunity. Notable beneficial effects have been seen on body weight gain, feed intake and feed efficiency in both broilers and laying hens. Cholecalciferol can provide beneficial effects on egg quality by increasing egg production, egg and shell weight, and shell strength by increasing thickness. It has a significant effect on the immune system and can help in the suppression of certain autoimmune diseases. The possible mechanisms contributing to these effects and the factors thought to explain the variability in these responses are discussed. Overall, cholecalciferol and its metabolites have been shown to greatly improve the performance of both types of commercial chickens, which can lead to enhanced production and a reduction in feed costs. The authors recommend a modified feeding programme containing higher levels of vitamin D3 supplementation than the NRC (1994) requirements in order to allow for sufficient skeletal growth in the starter and finisher diets of broilers.

Enzyme supplementation of poultry diets is nutritionally, economically and environmentally justified. Enzymes are used to increase the energy value of feed ingredients and enhance the utilisation of protein, fats, carbohydrates and phytin phosphorus from plant materials, leading to a lower excretion rate of undigested nutrients into the environment and, hence, reduced environmental pollution. This is especially important regarding proteases, as the correct digestion of nitrogenous compounds in feed materials is essential for reducing N excretion – a major pollutant worldwide. Numerous studies have shown no adverse effects of enzyme supplementation in broiler diets on body weight, mortality, health, feed intake, FCR, nutrient digestibility, meat quality and production costs. However, there is still a large amount of uncertainty regarding the use of enzymes.

Over the last five years, the costs of poultry feed ingredients have increased substantially. This has been due to an increased use of corn for ethanol production and a greater overall global feed grain demand. Across the poultry industry this has led to higher production costs and reaffirmed the importance of feed efficiency on profitability. The effect that an increase in feed costs has on profitability is a clear driver for the selection for birds with better feed efficiency. Feed efficiency selection can be achieved using a number of different analytical methods. Selection for feed conversion ratio (FCR) has been used to improve feed efficiency with success but using a ‘ratio’ trait has mathematical limitations because selection pressure tends to be placed on the component traits of FCR in a non-linear manner. Another measure, residual feed intake (RFI) shows moderate to high heritability and does not have the mathematical limitations associated with FCR. RFI has little to no correlation with production traits and this indicates that genetic improvement of RFI within a selection index can be done without the confounding issues inherent with FCR. Improvements in RFI or FCR have a favourable effect on environmental emissions and decreases the environmental impact of poultry production. The current global production of ammonia, CH4, and N2O by the poultry industry is significant, at levels of 2.1, 29.44 and 279 million tonnes CO2eq, respectively. Reductions in emissions can be achieved via improvements in feed efficiency by lowering amounts of manure excreted and decreasing emitted by-products such as ammonia and greenhouse gases (N2O, CO2 and CH4). Consequently, improvements in feed efficiency can not only increase profitability of the poultry industries by lowering production costs but also decrease environmental impact by reducing environmental emissions.

Poultry enteric diseases are an important economic problem involving many etiologic agents, including enteric viruses. Several viral agents have been detected around the world in enteric contents isolated from commercial chicken and turkeys flocks that initially appear healthy but exhibit enteric signs, such as diarrhoea, decreased food consumption, loss of body weight, and mortality. Chicken astrovirus, avian nephritis virus, chicken parvovirus, infectious bronchitis virus, fowl adenovirus group 1, avian reovirus, and avian rotavirus have been identified in chickens with enteric diseases. However, no single virus has been established as directly causative of enteric diseases. Knowledge of these viruses is minimal, and information regarding their role in enteric diseases is also scarce. This lack of knowledge, together with the important economic impact that enteric diseases have on poultry, justify the importance of their study. In the present review, all viruses involved in enteric diseases are discussed, with greater emphasis placed on those of the most prevalent.

Due to the high demands and production costs of the poultry industry it is imperative to study alternatives to modify the practice of incubation in order to maximise productivity by ensuring the conditions necessary for the development of embryos of current strains. Such changes in the management of incubation cannot affect the quality of chicks and broiler performance during early growth. To achieve these goals, several factors that work together during artificial incubation should be considered, for example, the relative humidity and turning machine incubators. Some research has already been conducted to define the optimum for these factors. This article reviews the results of studies where relative humidity and use of turning systems in incubators and their impact on incubation yield and chick performance were examined.

The increase in the productivity of the poultry industry has been accompanied by various impacts, including the emergence of a large variety of pathogens and bacterial resistance to antibiotics. These impacts are in part due to the haphazard use of chemotherapeutic agents as a result of management practices during the rearing period. Probiotic bacteria are defined as live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. This paper provides a review of the use of probiotics for the prevention of enteric disease in poultry, probiotic selection, isolation, colonisation and attachment within gastrointestinal tract, and the potential role of probiotics in nutrient metabolism. Understanding how probiotic bacteria exert their beneficial effect is crucial for the establishment of definitive selection criteria.

Injurious pecking is a serious concern for commercial turkey production and welfare. The behaviour is thought to represent re-directed ground foraging, but the development and causes are poorly understood with little supporting literature. In the initial development of the behaviour, early lighting regimes and social facilitation may play contributing roles. Other factors such as the availability of foraging material, diet composition, stocking densities, and group dynamics may also affect levels of injurious pecking. Given that commercial turkeys are group-housed, alternative breeding techniques, like group selection based on social effects, might successfully reduce moralities from pecking without detracting selection pressure from economic traits. However, to better suit their behavioural needs, any genetic attempts to adapt turkeys to perform less injurious pecking should be done in combination with environmental and dietary improvements.

Feather pecking (FP) in laying hens remains an important economic and welfare issue. This paper reviews the literature on causes of FP in laying hens. With the ban on conventional cages in the EU from 2012 and the expected future ban on beak trimming in many European countries, addressing this welfare issue has become more pressing than ever. The aim of this review paper is to provide a detailed overview of underlying principles of FP. FP is affected by many different factors and any approach to prevent or reduce FP in commercial flocks should acknowledge that fact and use a multifactorial approach to address this issue. Two forms of FP can be distinguished: gentle FP and severe FP. Severe FP causes the most welfare issues in commercial flocks. Severe FP is clearly related to feeding and foraging behaviour and its development seems to be enhanced in conditions where birds have difficulty in coping with environmental stressors. Stimulating feeding and foraging behaviour by providing high-fibre diets and suitable litter from an early age onwards, and controlling fear and stress levels through genetic selection, reducing maternal stress and improving the stockmanship skills of the farmer, together offer the best prospect for preventing or controlling FP.