In this study, the physical and microbiological quality and mineral composition of drinking water used in extensive poultry farms was assessed. Drinking water samples from 6 extensive laying hen farms were analysed for physical parameters such as temperature, dissolved oxygen, pH and electrical conductivity. The microbial examination of the drinking water samples revealed that the drinking water used in the extensive laying hen farms was not adequate. Similarly, the evaluation of the mineral and heavy metal concentrations of the drinking water samples showed that some heavy metals such as mercury were present in the samples in concentrations exceeding the legal standards. In the present study, to the best of our knowledge, for the first time a comprehensive evaluation of the mineral and heavy metal composition of the drinking water used in extensive poultry farms was accomplished.