would anyone know if they contain black walnut ? while they sell horse bedding / pine pellets for six or seven dollars for thirty pound bags- i can get pellet fuel for four dollars- anyone know if theres any added fuel or coating of any type that would harm a horse -someone told me there was fuel coating on it- i dont think so , i just got a harmon p68 six days ago- had some problem with the auger making screeching noise- they said it wasnt tightend right from the factory- came the same day i called and its quieter now then six days ago when they installed - all in all very happy but would like more information on the thermostat hook up- i just have a wire with metal end- do i need a thermostat attached or is that the sensory unit on the end of it ? thanks