Really and technically, you don't "need" to do anything. Major egg producers keep 2-4 birds in wire cages with LESS than 1 sq foot per bird, for up to 2 years and when they've passed their best laying and production drops, they are eliminated. Commonly called battery hens.So you're saying I have to build a run that's 220 square feet?
The chickens you buy at the grocery are kept in "houses" by the thousands, many with less than 1sqft per bird, but they are "designer" chickens that generally only live 6-8 weeks before being butchered. Designer meaning they are "meat birds" specifically bred to grow fast, put on lots of weight, FAST, and then they go to market.

Many here do buy meat birds for the freezer. Many keep them separated in chicken tractors. These can be moved daily or whenever while the birds grow out.

And most of us here keep chickens over many years time for their eggs and meat as well as companionship, entertainment and just the fun they provide. Some keep the meat birds right in with the rest, grow them out slower, and butcher them when they get to weight. Healthier for the birds and probably the consumers of them.
Many here consider their birds pets. "Ideally" the chickens require the space dictated to prevent overcrowding, disease, stress, feather picking, etc. As a general rule, the more chickens you have, the less space they need as most hang in groups, leaving "empty space" between each group. But still, there has to be the empty space for them all to move in and through. You do what you can do and shoot for the best.