The majority of my does apparently can either hear or sense electricity. My old waterer had a tank heater and my hard water corroded it fairly often resulting in the water becoming electrified. I always knew when that had happened because the does would walk towards it, reach a certain point in the pen, stop, raise their heads, look at it, then turn and walk away. After the tank heater was swapped out, they walked right up and drank. I don't know how common it is for that to happen, but it is something to consider.