We presently have our chickens in a 12' x 24' chain link dog run. We are in the PNW and get alot of rain and the run gets muddy. We also are in a constant fight with rats digging holes into the run. I saw a great idea for a way to roof the run in another thread and got the supplies for that this weekend. We will be moving the run to a different spot and leveling the area. I wanted to put down some hardware cloth then add some gravel and finish off with a layer of sand to about 6". I figure I will need something to keep the sand from pushing out the sides of the run and thought about putting down something like railroad ties for the perimeter and then attaching the chain link panels firmly to that. Also wanted to bring the hardware cloth up the sides a bit to help keep out the rats and maybe even add an electric wire around the bottom. Has anyone done something similar? I wonder if there is something I could use instead of railroad ties because they are pretty expensive. Any suggestions would be greatly appreciated.