I fed "field corn" over the winter. Read on here the corn helps them stay warm in the winter or something like that. I'll back it off as it gets warmer. Just flicked the kernals of a couple of ears each day.
I toss about a cup of scratch out too them every day. Just fling it over the huge run that I have and they scratch and dig all day.
I also toss out treats to them. Basicly anything that would go into my compost bin now goes into the chicken run.
Denali, your 16% protein feed isn't leaving much "room" for scratch.
Each day, a hen requires about:
120 grams of feed, containing 18 grams of protein and 320 calories.
The make-up of scratch varies greatly. The nutritional values of wheat and cracked corn, which are usually the main or only components, vary as well. Usually, scratch grains are neither high-quality nor high-protein. But, generally:
120 grams of whole wheat contains 15 grams of protein and 400 calories.
120 grams of corn contains 10 grams of protein and 440 calories.
I have read to only feed scratch and corn at roost time when it will be freezing or below. The reason not to feed it at morning time is so they will be sure to consume mainly their well-balanced complete feed ie: layer pellets or crumbles for laying hens. I like the Black Oil Sunflower Seeds for a daily treat, ususally about 3 P.M. or later; a small handful per chicken. Otherwise, once a week they get scrambled egg or old-fashioned cooked oatmeal with plain probiotic yogurt, and occasionally Romaine lettuce treats (usually in winter when there is less green grass available; they will jump up in the air for it!), melon, peeled chopped apple, Pepperjack cheese, and of course, Honey Nut Cheerios!
The key to treats is moderation. I fool mine by hand feeding them layer pellets since the best part of their day is treat time. They don't seem to realize it's not really a treat! There is a chicken treat chart on this forum with all sorts of GREAT info at the bottom of the page. You can find it in "Feeding Time" I think.