The overarching project objective is to investigate the causes of piling behaviour, a somewhat odd behavioural occurence where large numbers of laying hens congregate in dense piles of anywhere between a few to hundreds of animals. Most critically, the behaviour can result in animals being smothered and thus represents an obvious welfare problem. Our project is broken into two parts, the first part an exploratory effort involving data collection from 13 commerical farms with established piling problems following a preliminary questionnaire conducted by our group. On each farm, a range of data was collected including: environmental measures, behavioral data using video recordings, barn dimensions and features, and flock management protocols. Data from the first project is being used to develop hypotheses to test suspected triggers of piling that will be evaluated as part of a second project conducted at our dedicated research facilities within the Aviforum.