Thats fine. With a small backyard, you will contain the mess with a stationary place for your birds. We throw in fresh grass and fresh clover for them. We also sometimes dump the mowed grass in there. Then, when you are outside relaxing, gardening, grilling, or whatever, you can let them...
well, a chicken run is the best option for them - keeps them safe and gives them room to explore the area you have given to them. Next best is a fence around your yard, and clip the wings of your chickens so they cannot fly over.
What is your aversion to using a run? You can make it as large...