Factors related to free-range use in commercial laying hens

•Hens Out explained by genotype, flock size, roosters, plumage and ventilation type.•Hens Out in Dutch organic flocks explained by plumage and amount of daylight.•Hens Out in Swiss free-range flocks explained by roosters and rearing.•Hens Out in Swiss organic flocks explained by fear and genotype.•These results may contribute to improving range use by laying hens.