Excess calcium intake has been shown to reduce growth and feed efficiency and to increase bone ash and bone strength in growing chickens. Source and level of dietary phosphorus have been shown to affect calcium tolerance. The effects of high calcium can be largely explained by its effects on intestinal pH. The proposed mechanism involves excess calcium reducing the soluble fraction of minerals and the proportion of minerals in small complexes. In consequence, their availability for absorption is probably also reduced. The growth depression of chickens fed on diets high in calcium may be partly caused by the decreased availability of other minerals needed for growth. Calcium tolerance of growing chickens may be increased by ensuring that there are higher than normal levels of the other required minerals in the diet.

Poultry feeds and especially their animal byproduct components are a primary source of microbes to poultry. Current methods of microbial feed control do not consistently achieve eradication of organisms such as salmonella. Irradiation of poultry feed at predetermined doses results in complete destruction of salmonellae, enterobacteria, moulds, fungi and insects. Effective doses range from 10 to 40 kGy. There are no reported instances of adverse performance from birds eating irradiated feed, and radiation status of feed in unaffected.

This review on avian blood leucocyte responses to stress covers the literature from the early 1980s. It considers only non-infectious hormonal responses of leucocytes to stress mediated either by nutritional, parenteral, climatic/environmental (physical or social) or psychological stressors. The heterophil/lymphocyte (H/L) ratio after the administration of ACTH either in the diet or by injection and during food restriction studies has been studied. The ratio was found to be inadequate during severe food restriction studies, as some stressed birds responded with a heteropenia, lymphocytosis and a significant basophilia. Climatic and environmental stressors such as road transportation and heat stress produced significantly raised H/L ratios and basophilias, respectively. Psychological stressors such as fasting, frustration or noise showed different leucocytic responses and the times in which cells were mobilized also varied. Although the H/L ratio is a less variable indicator of avian stress than individual cell numbers and more reliable than corticosteroid levels in plasma, this rule applies only when mild to moderate stress exists. During extreme stress, as in life-threatening situations, a heteropenia and basophilia develop so the H/L ratio cannot always be accepted as an accurate measurement of stress in poultry. Thus, in some avian stress a two-phase cellular reaction may be present. This biphasic leucocytic response to stress may be unique to Aves.

Abstract Handling, in the context of this review, is the process whereby birds are removed from a building to a truck and, after transportation, from a truck to a building. The procedure includes collection, carrying to the transport vehicle, containerization (i.e. usually placing in crates) and loading onto the transporter. In general, most of these processes are carried out manually. Handling of poultry has been shown to be a potential cause of injury and, in addition, birds find human contact aversive. If mechanical devices could be developed that handled birds gently, close human contact could be reduced and there would be a potential to improve bird welfare. Several patented devices are discussed. The use of physiological and stress indicators in the evaluation of mechanical systems being developed can help to ensure that when brought into commercial use, bird welfare is not compromised during handling.

Survey data collected by the University of California have quantified some current systems of commercial egg production in the USA as a whole and in the state of California. Specific comparisons are made. Respondents were asked to estimate certain changes in the egg production sector between the present time and the year 2000. These projections suggest: a continuing trend for contract production to decline in favour of company owned sites; some further increase in cage rearing; more attention to improved methods of handling manure and disposing of dead birds; and a continuing growth in the number of large scale in-line egg production complexes. The projection that the size of the USA layer population will increase by over 20% by the end of the decade is considered unlikely to happen.

The first quail chicks imported into Estonia were hatched in 1967 and the first quail farm was built in 1976. Commercial quail production began in 1980 and 10 years later annual egg production had reached 7.1 million and annual production of meat birds was about 10 tonnes. The development of quail farming in Estonia has depended on several factors, particularly the development through selection of improved egg-meat strains and successful research into incubation, brooding, nutrition and the husbandry and management of both broiler and egg production stocks. Current levels of performance under commercial conditions are for egg production of up to 86% or 315 (per bird housed) from 35 to 400 days of age. Average feed consumption levels as low as 2.62 kg/kg egg mass are achieved. Estonian broiler quail males average about 140 g and females 150 g live weight at 35 days and are considerably heavier than the original Japanese stock. Average feed conversion (males and females) is as low as 2.83 kg/kg live weight.