We are having a particularly cold spell in Denmark at the moment. Every morning the water in the stone bird bath is frozen solid. But it is important that the birds have access to drinking and bathing water and we have solved this problem.
Every morning we boil the kettle and pour it over the frozen water to clear it of ice. The trough stands on the floor on two small tins. We then light 3 or 4 tea lights under the trough and fill the trough with warm water.
Regardless of the temperature, and we go below -20 in Denmark. The water will stay ice free for at least 5 hours, so the birds can use it.
It is not long before we get our first customers and it is lovely to stand in the kitchen and watch them.
When I learn to post photos on here I will share some.
Yes, that's my second job on really a cold morning - feed the horses, break the ice in their tubs, bring in the bird bowls. By the time I've had breakfast the bowls have thawed enough to tip the lumps of ice out, wash and refill. It's usually thawed enough by lunchtime to use the hose to top up the horses' tubs, I'm not keen on carrying all those buckets. If cold weather is forecast I make sure they are both full.