The continued use of antibiotics in poultry diets poses a health risk to the birds and humans, as bacteria develop resistance to such products. This study was aimed at identifying natural alternatives to antibiotics to control intestinal disorders in poultry. None of the test products was as efficient as an antibiotic but they showed some antibiotic qualities to different degrees and are worthy of further testing.

Changes in gut microbiota have been linked to altered feed efficiency in meat chicken. Molecular assays were developed to target several gut bacteria implicated in broiler performance and used to screen a series of feeding trials, where changes in lactobacilli and total bacteria were shown to be significantly linked to feed efficiency. These quantitative assays could be expanded to include other organisms of interest and used as a screening tool in evaluating dietary additives for improved broiler production.

Understanding the basis of variations in the efficiency with which production animals utilise food may allow the design of better production methods. We have compared gut gene expression and microbiota composition in chickens with extremes of energy use efficiency and have found differences. Further work is now required to determine if the differences can be harnessed to generally increase energy efficiency.

The human–animal relationship has consequences for the welfare of laying hens by determining how stressful they find human contact. The present study manipulated the human–animal relationship in commercial caged laying hens, and determined that close proximity, but not duration, of visual human contact was effective in reducing the behavioural response of hens to human approach. Stockpeople may consider working more closely to the cages to reduce fear of humans in their flock.

This study looked at a way to ‘ask’ hens about the relative importance of contact with other birds and access to a dustbath compared with access to feed using a Y maze choice test and results showed birds had a strong preference for feed over both contact with other birds and dustbathing access. These results were consistent with other similar research and indicate that this method of measuring bird preferences is a reliable and valid approach.

Egg quality was monitored in flocks of laying hens at different ages to investigate the importance of egg quality to the food safety of table eggs. Egg quality generally deteriorated with increasing flock age although the amount of cuticle present on the eggs did not vary with flock age. Changes in egg quality with flock age do not appear to be a risk factor for food safety.

In free-range systems, hens live in an open environment and may become prone to bacterial infections. Probiotics have been shown to prevent gastrointestinal infections. This study investigated the effects of two probiotics given in the drinking water. It was demonstrated that treatment with probiotics significantly improves reproductive tract health, reduces mortality and increases performance of free-range hens.

Odours and dust from poultry sheds can offend the surrounding community. The aim of this research was to measure the dust and odour emission rates from modern Australian poultry sheds. Odour and dust emission rates measured in this project will be useful to improve planning of new and expanding poultry farms and reduce the potential for impacts.