If you live in the north in an area with extreme winters and don't use supplemental lighting, chickens have to go through a long, cold night in mid-winter. I think it's a good thing to go to roost with a full crop. Whole and cracked grains take longer to empty out of the crop than processed feed, when they've done studies. I think it fuels the birds for more hours than a processed feed. It probably doesn't make that big a difference, but I think that's why people in the north have traditionally fed scratch at the end of the day in the winter. That's what they do around here, anyway.