last year I accidentally drop some black plastic in rain barrel and it got really cold that night and there was just a thin layer of ice, all of other buckets and plastic trash can froze solidA hammer would do no good, the water would freeze solid over night.
I do a couple of things.
I have a fount that sits on a heater in the coop. ( I know this sill shock some) but it is built for indoor use only, and UL approved. I use sand mixed with wood chips which are "damp" and I doubt would catch fire easily. I wish I could get them dryer...
This hold 6 gallons of water and I change it 2-3 times a week. I have a 2.5 gallon fount outside on a fount heater outside for the turkeys and chickens when outside. It is a 6 gallon heater good for 10 degrees. I get a weak ice on it when it gets below zero. Next year I will make a straw bale shelter around it and try 6 gallons again. The 6 gallon one froze this year.
I have 3 CX's in another building by themselves. they are my chubby babies. I carry them water everyday. They have a heated dog water bowl, I do not use the heater on it, as it is easy to carry the three water everyday. I use warm water and it stay thawed about 3 hours, they also eat snow, whether they have water or not,, dumb birds.
I look forward to the longer days when the water no longer freezes as fast.
BTW my coop is not near any other buildings, in case the heater shorts out.