I get alot of those biting cold days here, ya know when the wind is whipping through and its so cold your inner ears hurt.
BUT, it does not have to be bitter cold. If you think its cold out and would love a cup of hot chocolate to warm you up, they would probably like some hot mash.
Its a comfort thing.
Sometimes you can tell when they are cold, when they are huddling around together instead of running around the yard.
Finding a corner to bunk down in, heading back into the coop,stuff like that.
If its cold out and you give them cracked corn, its not going to hurt them, its going to help.
So just use your judgement, as long as its not summer then its fine.
The other things is, hot mash does not have to have the cracked corn in it to be hot mash.
You can use the crumbles and hot water, sometimes I throw oats/oatmeal in, whatever I have on hand or if I want to use up the last of something.
You may spoil them though, I have heard that can happen
I do it to keep them comfortable and laying eggs. If its too cold they can get stressed, even though most of my breeds should be cold hardy, there are some really bad cold days here and it doesn't hurt for me to go out in the morning or evening and give them something hot to eat and if it has the corn in it then it helps to keep them warm for longer.
Just make sure that corn or scratch does not comprise more than ten percent of their diet. So when I do the hot mash its mostly crumbles then a scoop of cracked corn or scratch thrown in.