Cheapest ways to feed chickens

So we have 20+ chickens and will be adding many more we live on an acre but hopefully will be moving to a much larger piece of land hopefully being able to give them so much more space. Right now we feed pellets and let out to free range in the evenings and in the summer they eat less feed then they do in the winter. We are basically looking for ways to break even all year long if not make a few extra bucks. So starting with feed. Other then doing more free ranging which at the moment in not an option as I have to be home cause we have a fox. So obviously feeding table scraps would help, but I do worry that it may get to be to fattening for them. We feed them old veggies or ones coming close to going bad, and I hope next year to plant a chicken friendly garden. So far I am feeding about 1 large scoop of feed for 18 ish chickens and some days they don't even eat that. Any other suggestions for feeding them on a small budget but still keeping them happy and healthy? All suggestions are appreciated. And if their are ways to get them off feed almost entirely that would be good to if it would be possible.
Just thought I would mention a system we are looking at doing and that is adding large runs off 3 sides of the coop and alternating which run is being used each week or every few weeks with some added free ranging in the evening.
I would also like to mention I realize it will be hard to make any if only a little profit, but would like to try.

Your idea of making multiple pens for rotating pasture is your best bet.
If it gets cold where you live, that will only work for 3 seasons.
I keep 40 to 100 chickens on 3/4 acre for eggs and meat.
Right now I have the most layers(38) I've had in many years. I only make enough to pay for all the animals' and feed ourselves eggs and meat.
IMO there is no way to make a profit on such a small flock because you can't buy feed in bulk and a small holder is likely to keep their birds through molts and beyond when they aren't producing much.
For your pasture you can plant buckwheat, turnips, radish, clover, alfalfa, ladino, vetch, wheat and oats(depending on season).
Getting enough protein from pasture is only possible in warm weather when bugs abound.
Otherwise the chickens will quickly go through those sources and be hurting for sufficient protein.
You can try to find a protein source like bagged fishmeal, meatmeal or scraps from a meat market.

You might not like my answer, but I think the cheapest way to feed them is to give them a good quality feed such as Purina Layena or Flock Raiser. I buy 50 lb. bags kept in a metal can, and a $16-17 bag lasts about 10 days for my 36 chickens. Mine eat crumbles better, but if I put water in a big tub with pellets, they eat every bit. Dog and cat food costs a lot more, and the store brands of chicken feed (TSC and Southern States) are cheaper, but not as high quality, and I've tried them all. They need at least 16% protein in their diet.You don't need to give them anything else really, but some people like to give scraps--I just don't have many. If they free-range, they will eat less food, but I think they should always have plenty out during the day.

The cheapest way, actually, would be not to buy feed at all. Not always practical for everyone, but anyone can take some steps in that direction. Check out the "Home Feeding Solutions" thread on this forum. You might get some really good ideas to help you out there...