I am fighting a sparrow war, too. Over the summer they not only figured out how to get into the run, but they were entering the coop a dozen at a time and gobbling up all the food inside and staying overnight. Nothing like opening the people-door in the morning and getting a faceful of panicked sparrows! I took a piece of heavy garden cloth and cut strips into it, then tacked it inside the pop door to the coop. I had to gradually acclimate the chickens to the concept of walking through it by tacking back a few strands to make an opening in the beginning, but now they're pros and they go in and out through the strands in the cloth. No more sparrows inside the coop. Next step is to tack the cloth over the entrance to their enclosure, where I hang another feeder. It won't stop the sparrows from entering their run and helping themselves to the scratch, but it's already making a huge difference in the amount of feed I go through in a day.