The railings from our old pontoon boat have been sitting on a Hobie Cat in my driveway for a while, waiting for me to either recycle the aluminum or find a purpose for them. Glad I never got around to recycling them because I figured out that they would make a good frame for a chicken run extension.
I used zip ties to attach wire mesh to the sides and top and then pushed it against the open lower door of the Eglu chicken run. Because Luke the Cowdog or some other critter might be able to push it aside, I put a couple of bungees on either side.
The chickens were very cautious at first but quickly realized the new run extension is a place where I hand out meal worms and then took right to it. They seem to enjoy having a bit more room to run around.