Gamekeepers and even poachers were particularly valued. British gamekeepers have used rock salt shells to deter poachers. He showed sympathy with both poachers and gamekeepers. It is the most widely used magpie population control method amongst gamekeepers and conservationists. There were also grooms, chauffeurs and gamekeepers. They would often offer these players full-time employment as gardeners or gamekeepers on their estates. This may be due to ongoing persecution and trapping by local gamekeepers. The act also established the need for game licences and the appointing of gamekeepers. According to a Polish royal survey in 1564, the gamekeepers knew of 38 animals.