about the effects of housing systems on the quality of the eggs exceedingly difficult. Consumer perceptions of these alternative systems delivering a better product are then scientifically unjustified in terms of there being any nutritional difference. A 2011 research study carried out in North Carolina compared free-range and conventional caged eggs for fatty acids, cholesterol, vitamins A and E, finding higher fat content in free-range eggs, and no significant difference in cholesterol and vitamin levels. Vitamin D in eggs has been observed to increase up to 4 times in hens that have exposure to sunlight, compared to hens that are kept away from sunlight. Another research suggests that grass fed hens can produce eggs that are rich in (n−3) fatty acids, without adverse oxidative effects. Some other non peer-reviewed studies have found evidence for nutritional benefit of free-range eggs. Retailers Several major retailers have a policy of selling only free-range eggs, or, not selling battery-cage eggs. Some retailers apply this policy not just to eggs in their shells, but also to eggs used in baked goods and processed products such as ready-made meals, quiches and ice cream. range shell eggs, and uses only free-range eggs in their processed products and ready-made meals. As of 1 January 2007 (with one minor exception), all Austrian supermarkets no longer sell battery eggs. Many retailers in the Netherlands, including Albert Heijn and Schuitema (subsidiaries of Ahold), Laurus (including Edah, Konmar and Super de Boer), Dirk van den Broek (including Bas van der Heijden and Digros), Aldi and Lidl sell only free-range shell eggs; however the free-range eggs that are sold in Aldi and Lidl do not meet some country's recommendations for the production of free-range eggs. Three Belgian supermarkets: Makro, Colruyt and Lidl, no longer sell battery eggs. The Commission's report states that Sweden's move away from conventional battery cages has been aided by the decision by the four largest retailers (who between them account for 98-99% of the Swedish retail market) to stop stocking conventional battery eggs. U.S. food suppliers Aramark and Unilever have announced they intend to buy only cage-free eggs, but as of 2013 there are not enough available to supply them. In Australia free-range eggs that are sold in Aldi and Lidl do not meet the CSIRO's Model Code recommendation of 1,500 hens per hectare. In March 2016, Australian ministers voted in new standards for the definition of free-range. The