Sainmhíniú eggs laid by hens that are stocked at a density of no more than 25 birds per square metre on the floor and the building has sufficient perching to allow a minimum of 15 cm of perching for every bird Tagairt "Warrington Borough Council > Advice & benefits > Trading standards > Guidance Notes > Free Range & Other Special Marketing Term Eggs, http://www.warrington.gov.uk/adviceandbenefits/Tradingstandards/guidance/Guidance_FFRE.aspx (14.5.2009)"