Ann Duck was baptised on 22 July 1717 in Cheam, Surrey, shortly before her parents married. Her father, John Duck, was Black, whilst her mother Ann was white. Her father had been in service with Edward Green of Nonsuch Park, near Cheam but became a teacher of swordsmanship to men at the London inns of court soon after he married. The Duck family lived in Little White's Alley, just off Chancery Lane. Ann had at least three younger siblings: John (bap. 1719), Elizabeth (bap. 1724, bur. 1727) and Mary (bap. 1729).[2]
Ann learned to read and write, and to do accounts, and is thought to have worked as a shop assistant for a time.[2]
In September 1740 her brother John sailed with Commodore Anson's squadron to South America aboard HMS Wager, which was wrecked off the coast of Chile eight months later – a crewmate claimed that he was later sold into slavery on account of his skin colour.[3]
Their father John died in October 1740, which left the household without male earnings.[2]