I was feeling a little guilty leaving the chickens locked up in their run and coop area during the day while we were at work because there wasn't much room to spread their wings. The original run was about 3 by 8 feet or 24 square feet. That's only 3 square feet per bird. So while my husband was off of work for the summer, he built them a larger run that would attach to the old one. It is 8 by 8 feet and made of the same materials and paint color as the hens' original home.
With the same type of wheels used on the original coop and run, we can still move the enclosures around the yard and continue with our rotational grazing, which means moving the coop every couple of days. This does a few things; it keeps the ground from getting to worn from chickens scratching, less manure in one place which would be a messy environment for the birds and gives them fresh areas to forage for seeds and bugs.
It seems to work pretty well. It's not the same as the rotational grazing practiced at Polyface Farm you may have read about in the Omnivore's Dilemma which was a system of grazing by cows on specific grasses and chickens systematically moving behind them to clean up the earth. This is much simpler because we only have one species working the land.
Something I'd like to put into place with the birds this winter is allowing them graze in the empty vegetable garden. Not only will they keep the over-wintering insects at bay, they will also keep weeds from rooting, stir up the dirt and provide the area with nutrition in the form of chicken manure. This in addition to the lovely compost I'm continuing to make in the bin will hopefully make for a better crop of tomatoes next summer.