Eben Ernest Hayes was born at Monks Kirby, Warwickshire, England, on 4 February 1851. He was the first of 10 children of Hannah Jones and her husband, Ebenezer Hayes, a mole catcher. Ernest, as he was known, was educated locally and then served an apprenticeship as a millwright, gaining experience in fitting and turning, remodelling machinery and dressing millstones. He married Hannah Eleanora Pearson at Whitington, Norfolk, on 15 February 1881. The couple, with their first child, Llewellyn, emigrated to New Zealand, arriving at Port Chalmers on the Taranaki on 14 November 1882. They were to have five sons and five daughters (one stillborn).
The family settled in Central Otago where Ernest went to work at Ophir. He put his skills to work installing machinery in the Vincent Flour Mill, which he ran for his uncle, Josiah C. Jones. In 1884 he moved to Rough Ridge (Oturehua), where he managed a flour mill until 1900. Ernest became first chairman of the Rough Ridge School Committee, and Hannah, the school's sewing teacher.
Meanwhile they were developing a 150-acre farm. The family lived in a cottage with an adjacent small workshop, and Ernest Hayes began to invent tools to help him carry out his farm work. At first they were made by hand and then on a hand-operated lathe constructed from a gate-post and a chaff-cutter wheel. In 1895 he devised cutters to make pellets from strips of rabbit poison. Buyers for the cutters were initially hard to find and Hannah went out seeking orders. Leaving one of her older daughters to look after the family she bicycled throughout Maniototo and Vincent counties, as far as the Lindis Pass and the Mackenzie Country.
In 1902 Ernest Hayes began serious engineering production. In 1905 he set up a small forge and began to produce a series of simple but efficient farm implements: the 'Monkey' brand wire-strainer, a cart jack and a wire-coiler. He became best known, however, for his invention of the parallel wire-strainer for farm fences, which rapidly found a market throughout the country.
An early experiment with a cone windmill to produce power for the works failed, but about 1910 Hayes succeeded in building a windmill with a 40-foot tower surmounted by multi-bladed sails 22 feet in diameter. Power was transferred to the workshop through a complicated arrangement of shafts, belts and pulleys, but the unreliability of wind power finally led to the dismantling of the windmill and its replacement in 1927 by a water-wheel.
Hayes's experience with windmills had led in 1912 to the production of the Hayes farm windmill for pumping water. These were to become a familiar sight in many country areas. Other products followed: pulley blocks and cattle-stops, and a lever device for lifting subsided fence standards. The plant was continually upgraded to meet the needs of expanding production. A new workshop had been followed by a packing and store room in 1908, a fitting shop the following year and a further extension in 1914. Ernest and Hannah Hayes's sons joined the business, and between 1919 and 1921 the family built a large villa on the Oturehua property. An export market for Hayes's products had developed by 1926 when Ernest Hayes retired in ill health, and the engineering works were at the peak of production when he died at his home on 27 June 1933. The business shifted to Christchurch in 1952. Hannah Hayes had died on 2 June 1946.
A pioneer in the manufacture of labour-saving appliances and machinery for farm and station, Ernest Hayes had used his capacity for solving technical problems to invent articles which were ingenious in design, simple but strong, and easy to use. From a remote workshop farm he achieved a national reputation for his products. The Hayes Engineering Works at Oturehua was purchased by the New Zealand Historic Places Trust in 1975.