The chickens roost in a mobile coop that is moved to new grass/forest weekly. They are protected by a moveable electric fence and the many crows and ravens that guard our compost pile.
In addition to grain, the chickens eat bugs, grass, and plenty of food scraps. During tomato season, they fight over the hornworms that get plucked from the plants.
We have fewer eggs during the winter, but hay gets spread around the coop after each snowstorm, and the chickens still spend most of their time outside, despite the cold.
Eggs are $5 a dozen (that's only 42 cents per egg). Any less, and we'd have to purchase low-quality feed.