Grey won the business after a pitch, which kicked off in September, handled by ISBA.
The company, which also owns the Abbot Ale and Ruddles County brands, appointed Dare to the advertising account for Old Speckled Hen in March 2009. Dare did not repitch for the business.
In July, the brewer, which also runs one of the UK's largest estates of pubs and hotels, launched a series of idents to support Old Speckled Hen on the digital channel Dave.
Greene King, which has been based in Suffolk since 1799, launched the review at a tough time for the beer and pub trade.
In a trading update in September, Greene King warned of an "uncertain" outlook despite an increase of 1.8 per cent in volume sales of its brands in the 18 weeks to 4 September.