How big are your handsfor example, don't give more than a handful of scratch daily for so many chickens

My girls (20 currently) get a 5.5oz cat food can of BOSS in the morning and the same of scratch in the evening. They also get a 56(?) oz jar of layer feed morning and evening. I guess that approximates the 10%rule, quite by accident. No way they nicely make sure each hen gets an equal share of the treats.
When there isn't snow on the ground they go out and eat whatever they find of interest.