"Free Ranging" isn't defined in the US based on square footage - and the definition that is Congressionally authorized is not what people think of, when they imagine "Free Ranging". Nor is "Pasture Fed". I wouldn't worry so much about the labels, and would recommend only that you provide them as much room as you reasonably can.
From a cost perspective, my birds range about 4.5 acres (you can see my flock in the sig below, usually runs 50-55 birds), of which about 1.5 acres is pasture of biodiverse polycrop (which is to say its been seeded with anything and everything I can get to grow on my property, not toxic to chickens or goats, which requires little care on my part). It saves me 20-25% on my feed bill.
As to the feed bill itself? I buy in (small) bulk, pay cash for the discount, 500# at a time. Assuming prices have increased for the sixth time in the last 12 months, I expect to pay about $115 after tax, or around $0.23 a pound. My break even on eggs, without cartons, is right around $5/30 eggs or $2.50 a dozen (licensing costs are a substantial part of that). While I am "underpriced" compared to almost everywhere in the country, I have a decided lack of customers for lots of reasons unrelated to egg size, quality, or freshness.
You probably want to go back and double check both your math, and your assumptions, on that break even price. It seems very low.