I have had good luck with fermenting scratch. I feed a bit of the water-soaked grain. Even if it freezes solid, it can be picked apart, where as the fermented crumbles, just froze in a solid block, and mine did not eat it. The soaked grain, helped them get a bit of extra moisture too.
Wind breaks, really help. Encourages them to go out, get some exercise and fresh air. Makes them eat better.
I think the weather does influence how much they eat. I try and do it so that at night, there is very little left in the bowl. If empty, I feed a bit more the next day, if still quite a bit left, I feed less.
Mrs K