I've switched to ceramic which are slightly more reliable and use 2 when temps are below 60.Ice on every bucket here too at 27 degrees. Second cold morning, but more ice as thehigh temp yesterday wasn't very high.
Looks cozy. I worry about the lamp going out. Pros and cons to every method, right?
I also have 2 hovers with 2 lampholders each when I have more than a few birds.