There is a short article about Free Range Eggs compared to Pastured Eggs
The website is about a Farmers Market in San
Francisco, one of their new vendors, Shelly Mcmahon of Shelly's
Garden, produces eggs with pastured chickens.
The article starts about the middle of the page.
This might give you ideas about
your own flock of heritage chickens on your farm. Or you might think
about diversifying your current poultry or rabbit farm.