I have a small flock of chickens who spend the night in a coop with an attached run. During the day, the girls are let out into an enclosed chicken yard and the door to the run is left open. The door is out 6' tall so that I can get into it. The run contains their food & water. The food is in a large feeder that I fill about every 10 days with 25 pounds of pellets. They girls do in & out all day long to get to their nest boxes & the food & water. Lately, I've noticed small birds, wrens I think, flying in and out the run. evidently eating the chicken feed. A couple of weeks ago, I attached a piece of netting to the top of the door opening, ending about 1' from the ground. The chickens can still get in & out & it stopped the wrens for a few days. But the wrens were smart enough to eventually figure out they could get in from the bottom, so I'm back to the same problem. Can anyone think of any solution to my problem? The chicken food is being eaten up much faster than it has in the past. Plus I'm worried about any diseases that wild birds could be carrying.