The concept is very simple. Ideally, seven neighbors who are interested in owning backyard chickens form a co-op, however, any size group will work. The biggest challenge is finding the home owner willing to house the chicken coop on his or her property. Once that hurdle is met, the coop needs to be designed and built and the chickens need to be selected, and purchased. From then on, each co-op member shares the expenses and responsibility of caring for the chickens one day a week. As a member, your assigned work day of the week is also the day you are privileged to gather the eggs.
One obvious advantage with this co-op type of arrangement is that you don't have to be a homeowner to be a chicken owner. The advantage for the coop host is that he or she can own chickens with less work and responsibility, especially for someone who travels frequently. There is the positive aspect of social gain and neighborhood strengthening involved in this type of set-up, too.
The photos that I am using in this post are from just such a co-op here in Boulder which happens to be very near the famous Pearl Street in downtown Boulder. You would never know it. The owner of a large rental home was onboard to host the chicken coop in her backyard. She also gardens this same backyard. See next photo.
The photo below shows the chickens eating inside their coop. The photo at the very beginning of this post shows the coop's exterior drop down opening used to gather eggs without disturbing the hens.
This final photo shows one of the proud members of this co-op holding a very tame chicken.