Fujara overtone flute was an instrument of Slovak shepherd's. Since the shepherd were all alone and played for themselfs and the sheep, there was no need to tune the Fujara flute to any key. Fujara was and still remains mostly a solo instrument. Thus, old, traditionaly made Fujara flutes are usually not tuned to any key.
Fujara was mostly played by shepherding. Allegedly, the Fujara flute sounded most beautifully when it had been played behind the sheep, just step by step, side to side. The Fujara flute's soft voice and its slow melody calmed the sheep and they could better and peacefully nibble. Today, the experts for ecological (alternative) farming would say that a "welfare effect" was achieved, which means that an additional comfort for animals was reached manifested in their vitality and better utility.