I have an area about 24 ft x 14 feet, with many layers of pea gravel from when I used to have dogs in the 70's. Every year I used to add several inches, so it has a deep base. - with clay fill underneath that. Drainage is great but it is very easy for any critter to dig holes thru it. Grass doesn't grow there but a ton of weeds sure do.Would this make a decent area for a chicken run or would the back yard be better. Our area of town has rocks everywhere, you can't plant a tulip bulb without the shovel scraping on rocks from baseball size to boulders that would have could have the ten commandments written on them. Most times when you excavate a boulder the ground level drops a foot, with no dirt to fill in, we'd just put them back and recover em. Drainage is good and digging is hard I guess unless you are a motivated predator. Sure wish I kept the old dog runs -they were a good price even for back in the late 60's and heavy guage chainlink with one inch mesh that I sure don't find anywhere now.THanks for any suggestions or advice.