Isn't it true that hot or warm water freezes quicker than cold though? 
the water vapour will freeze, it has a small surface area, so in closed container like a poultry drinker, or water bottle will freeze faster.
I have a sink full of the guinea pig & rabbit bottles that are literally frozen solid, since being done and refilled this morning.
I've run out of spares, they are all in use or defrosting in a never ending cycle! 
Our goats & pigs are getting warm water, once I ve broken the ice everyday  
