I use a 44 quart tote with lid, horizontal nipples, and a stock tank deicer that is okay to use in plastic.  Keeps my 12 chickens in water for over a week.  Water stays clean and thawed.  Last winter it got down to -22.  I went out to check on the water.  Water was still thawed.  I have a heated dog dish for backup just in case my system ever breaks down.  My system is going on its 4th year now and has never frozen.
	
		
			
		
		
	
				
			
	
  ...plus pics are worth a thousand words!