I am SO glad to hear that others exert effort to make things interesting for their flock when it snows! I thought I was the only wierdo out there shoveling paths for them. I spread some pine needles on the paths to make it easier for them to venture out...
Getting down to bare ground is a big hit, and then if you shove a pitchfork in to loosen things up, the party begins... Of course the dominant chicken always gets first dibs on any thing good.
Growing trays of wheat grass is not very difficult, and after the first few cuttings, which they gobble up very fast, you can let them go at the whole tray. It's funny to see them do their "scratch scratch scratch, dip" (reminds me of a country line dance) right in the growing tray.
This probably won't work up north where you get a ton of snow, but if we know the night before that it's going to snow we make a lean-to shelter from a tarp along the south side of the house, then there's a snow-free space for them to hang out in the next day. Some birdseed and scratch thrown in gives them enough to keep them occupied, for a while at least. Then they just kind of sit there and "be", contemplating the nature of the Universe.