OK, they just cluck, cluck, Sounds friendly enough. Maybe the "purring" thing is in a breed? What breeds do you have? I once had some RIR (Road island red) They did purr but seemed like only in the summer. The warmth maybe? Welll ... maybe you could help me with my research in another way. Do you use any energy saving devices, solar power, wind power, steam etc.? Thanks in advance DHL