I have given up FF in any unheated dishes unless it's the weekend and I'm home to refill a few hours later, because it freezes really fast. The silkies get it all the time because they were blessed with a heated dog bowlWe are at -2 here this morning... I offer water every 4 hours during the daylight but that's about it. No heat or heat lamps. Breeding pens don't even have a front normally but I did hang a tarp to break the wind.
Since I feed FF I simply offer each coop a few spoonfuls throughout the day and keep the bowls inside with the rest the day's feed.
My birds are all out of the wind and happy and fine... they are a lot warmer and hardier than people think.

They are finally starting to accept the dry feed.. they hated it at first.