This is my first winter with chickens, and I have learned a number of lessons. I plan on building an A Frame type of removable panels so I can make an area in the chicken run that is not 3 feet high in snow. I imagine the panels to be made out of a wooden frame, using some wire to hold it together and provide some strength, and then covered with a clear plastic to keep the snow out. The A Frame design should let the snow slide off and down the plastic. The plastic covered sides should act like a mini greenhouse and keep it just a bit warmer inside the A Frame if the sun is shinning. Anyway, that's my current thinking.
One thing I did do right was assume that my chickens would not want to go outside in the run covered with snow. I built my chicken coop about twice the size recommended for the number of chickens I have (I have almost 8 square feet per bird in the coop). This has worked out good because my chickens have rarely gone outside this winter. But there is easily 2 feet of snow in the chicken run and drifts about 3 feet high.
More to the issue of winter feeding fodder, for where I live, is that it has really worked out much better for me to let the fodder bin(s) dry out for the last day or two in a sunny window and then feed the fodder to the chickens. Previously, my fresh, green, damp fodder directly from the fodder tower froze like a green iceberg in our temps this winter and the chickens would not eat frozen fodder. So drying out the bin for that last day or two, and cutting back to half a bin of fodder per morning, was just the right combination of adjustments needed for my 10 chcikens.