Another thing i do for my chickens, mainly for their entertainment because they eat plenty, I create microhabitats for cockroaches and crickets, and at least once a week I can feed the flock for a treat that day.
Cockroaches i grow using cardboard boxes, its as simple as stacking them in a corner for a couple weeks. A good harvest can yield maybe 50 cockroaches for my small scale operation. Crickets grow outside all over, but mainly under rocks or inside plastic tarps. They are much more plentiful, a single rock can house a dozen or two. I can fold a tarp up and grow a lot.
I don't think my chickens ever had oats or grains. I tried feeding them oatmeal and they arent interested. I can't understand the charts and numbers what they mean, i will ask around to see if i can buy oats and try it. Im always interested in variety, because corn makes up at least 40% of my flocks diet, i love adding variety because i know it is defiecient, but in a way it is sufficient supplement to free range. Also the corn greens that sprout are microgreens which are very healthy.
Microgreens is another option for this thread to consider as well. I grow onions and cilantro, but the chickens eat the sprouts, which are very healthy. You would have to set up an indoor hydroponic microgreen garden if winter was too cold to grow. A lot of people do grow hydroponic plants to feed animals, grass for example in very arid climates.