Experimental design: minimizing the number of subjects that suffer may not mean minimizing total suffering

A non-intrusive method of assessing plumage condition in commercial flocks of laying hens

Standard techniques for assessing plumage damage to hens from feather pecking typically require capture and handling. Handling of individual birds for plumage assessment is relatively easy in experimental studies; however, close inspection of individual birds in commercial flocks is less feasible because catching birds is difficult, may compromise bird welfare and affect egg production. The […]

The ecology of individuals-incidence and implications for individual specialization

Most empirical and theoretical studies of resource use and population dynamics treat conspecific individuals as ecologically equivalent. This simplification is only justified if interindividual niche variation is rare, weak, or has a trivial effect on ecological processes. This article reviews the incidence, degree, causes, and implications of individual-level niche variation to challenge these simplifications. Evidence […]

Methods for calculating activity budgets compared: a case study using orangutans

The results of comparisons of behavioral data between individuals, age–sex classes, seasons, sites and possibly even species may depend on sample size and the computational method used. To establish whether these are valid concerns, we compared results for percentage time spent feeding on major food types (fruit, leaves, flowers, invertebrates, bark, pith and other) for […]

Statistical power, effect size and animal welfare: recommendations for good practice

Despite the particular relevance of statistical power to animal welfare studies, we noticed an apparent lack of sufficient information reported in papers published in Animal Welfare to facilitate post hoc calculation of statistical power for use in meta-analyses. We therefore conducted a survey of all papers published in Animal Welfare in 2009 to assess compliance […]

A comparison of inferential analysis methods for multilevel studies: Implications for drawing conclusions in animal welfare science

Investigations comparing the behaviour and welfare of animals in different environments have led to mixed and often conflicting results. These could arise from genuine differences in welfare, poor validity of indicators, low statistical power, publication bias, or inappropriate statistical analysis. Our aim was to investigate the effects of using four approaches for inferential analysis of […]