from DEFRA website;
Why are eggs not refrigerated?
Before purchase by the consumer, EC legislation requires that eggs are stored and transported at a preferably constant temperature. This is current practice within the UK egg industry and the reason why the majority of retail outlets' egg displays are not refrigerated. Changes in storage temperature and humidity can lead to condensation forming on the egg shell which can cause mould growth together with the possibility that any bacteria may infect the eggs as a result. After purchase, the consumer is advised to refrigerate the eggs to maintain freshness and reduce the possibility of bacteria growth resulting from exposure to the temperature and humidity variations of the domestic kitchen.
http://archive.defra....try/faq/marketing.htm