Abstract Piling is an understudied group behaviour where chickens gather in dense clusters. It appears to be widespread in commercial laying hens, leads to mortalities (smothers) and impacts production. Automated detection of piling could support: (i) stockpersons to reduce the behaviour and (ii) scientific efforts to study the behaviour. Computer vision-based classification is increasingly used in animal behaviour research to accelerate annotation of datasets. Here we aimed to automatically det