Allied Precision IndustriesHeated Chicken Waterer

Because of the distance of the coop to and outlet. Can I use a heavy duty extension cord to operate this watered?

Can I buy just the top piece? And if so where?

I just got my electric chicken water I was wondering I want to use it in the summer months do I leave the cord on it or does the cord come off?

We live where temperatures can often be below zero. Is there a point at which the heater is unable to keep the water from freezing ?