I wouldn't feed only scraps as well.
You can ration out feed for the layers by calculating about 1.5oz per lbs. of mature chicken if they are free ranging. Put no more than that in a feeder per day and see if they eat it all or not if you're running tight on feed. If they eat every drop, increase it to 2oz. per pound per day. If they do not, then decrease it again, by .5oz, until you find the ratio. To get more worth out of a bag of feed, try fermenting it. Feed less, less smell, etc. But they may consume more feed by volume and weight (but remember there is water added).
If you're looking to store feed for winter, I'd suggest getting the cheapest gallon jug of Red Cell for horses (with chelated Iron). Costs from $20-$30 but it will last probably 1-2 years. Stored grain looses nutrition and thus, less laying, more eating, and wasted money. A quarter size/2 teaspoons of Red Cell in the water or fermented grain replaced minerals and vitamins only. You only need to add this 1-2 times a week, the rest of the time just normal or ACV water.
If you wanted the scraps to take out a portion of the grain consumption, they have to be high nutrition and given right before roosting or right as they wake (when they gorge) and then you'll see the greatest reduction of feed cost.
