establishment loans and sustenance payments and by 1922 some of the original occupiers had abandoned the project leaving the blocks for other ex-servicemen to take over. Over the next three decades the farms were turned over to other activities or further subdivided and by the 1950s none were being used for poultry farming although many such enterprises had been successfully established in the surrounding districts principally by migrants from Europe. In 1923 the "Grantham State Poultry Farm" was no longer required for the settlement scheme and passed to the Department of Agriculture for use as a demonstration farm and named the "Government Poultry Farm". In 1939 the farm's function changed to one of experimentation and research aimed at improving the quality of the poultry farming in the state. This led to yet another change in name with the farm becoming known as "Poultry Experiment Farm, Seven Hills". From the 1940s the farm was the site of ground breaking research (notably by Professor Bill McClymont and Dr Len Hart) into poultry husbandry and nutrition leading to significant improvements in the efficiency of poultry farming in Australia and overseas. This was officially recognised when the name was changed to the Poultry Research Station in 1960. In 1971 a new building was erected to house research and administrative functions of the research station and (later) offices of the NSW Egg Marketing Board. By 1983 the site was known as "Agricultural Station, Seven Hills" and operations had begun to wind down. Much of the Department of Agriculture land was declared surplus to requirements and by 1989 the station had closed and the land sold off for residential development. In 2004 the remnant of the estate including "Melrose", "Drumtochty" (by now moved to the northern end of the estate) and the administrative building were acquired the City of Blacktown. In 2008 a plan for the use of the administration building as council offices and the development of the lands as a heritage park was announced and public comment was invited. The remnant portion has been named "Grantham Heritage Park". The entire estate, including Melrose and Drumtochty, is heritage-listed. The park lands contain some of the last vestiges of Cumberland Plain woodlands and the Grantham Heritage Park Memorial commemorating the soldier settlers and trainees. Heritage listings Seven Hills has a number of heritage-listed sites, including: 37-39 Roger Place: Dayton House 71 Seven Hills Road: Grantham Poultry