Sandringham continues to operate as a sporting estate. Pheasants and partridge are no longer reared for this purpose, and Sandringham is now one of the few wild shoots in England. Along with her equestrian interest in the Sandringham Stud, where she has bred several winning horses, the Queen has developed a successful gun dog breeding programme at Sandringham. Following the tradition of a kennels at Sandringham established by her great grandfather, when Queen Alexandra kept over 100 dogs on the estate, the Queen prefers black labrador retrievers, over the yellow type favoured by her father, and the terriers bred by her earlier predecessors. Since his retirement from official duties in August 2017, the Duke of Edinburgh has spent increasing amounts of time at Wood Farm, a large farmhouse on the Sandringham Estate used by the Duke and the Queen when not hosting guests at the main house. Sandringham is one of the two homes owned by the Queen in her private capacity, rather than as head of state, the other being Balmoral Castle.