Hello! Yes, I give my flock scratch in the winter time. I just throw out some handfuls in their chicken run, just before dark, and they come running from all directions (I let mine free range during the day). So the scratch entices them to come inside and I lock them all in safely for the night.
I would say for five pullets, throw down a good cup of scratch. It gives them something to scratch at and peck around for. It also causes their bodies to warm up a bit, during digestion.
Just a tip, in the wintertime, if your birds are locked up and don't have access to the outdoors, be sure and offer them grit. It's vital to digestion, and it'll help grind down that scratch.
Take care!
Sharon