I discovered a very small opening in the pen. It was also hidden under stairs from the outside. One chicken found her way out. I set up an obstacle course out of the hole Pretty soon all 6 chickens were able to get out to the yard each morning and find their way back in at twilight. This has gone on over a year with no predators getting in, o We live in the Rockies with many big predators and all is going well. However in Denver in the flatlands they are loaded with coyotes who are killing many pets and chickens. Not up here. For flying predators (eagles, crows, hawks, etc) I made scary looking birds and hung them out. I painted a one gallon milk jug black and then painted 2 huge yellow eyes with big red pupils on the handle side where I attached a small rope for hanging. Then hung old video tape from it flying in the breeze. I made 2 and going on one year now, no attacks. The 2 huge eyes are on the top side so they can been seen from above.