Commercial rollaway group-nests used in free-run housing systems range in floor surface area from approximately 0.5 to 1.8 m2, with a relatively constant depth of 0.5 to 0.6 m and a width of up to 3 m. Legal requirements exist for group-nests in a few countries but they only pertain to the maximum number of hens allowed per m2 of nest sur- face area: 100 hens per m2 in Switzerland (Animal Welfare Ordinance, 2008) and 120 hens per m2 in the EU and New Zealand. In Switzerland, commercial farm animal housing systems or equipment, including nests for laying hens, must be approved by the Federal Veterinary Office before they can be sold to producers. Therefore, various nest properties have recently been examined experimentally.