I had a giant log that was mostly hollow. Half of it is in the run, and the other half in the coop. They love climbing on it, looking for goodies in the bark, and during integration time the chicks dash under it if the bigger birds get too pushy. I also have a big tree branch hung in the run and it swings. Another favorite. There is also another branch that doesn't move.
I cram veggies or watermelon or apples into those little wire suet cages for feeding wild birds. They go nuts. I hang them from the side of the run and since they move freely the girls really have to work to get the treats. A big rubber container holds dirt for them to dust bathe in. And of course for pure entertainment, keeping litter stirred up, and getting them back into the run at the end of free range time, nothing beats a handful of scratch tossed into the run. Some of it inevitably ends up in the bark of that log, and they get up on top of that thing and patrol diligently.
This was taken when the broody pen was still set up in the run, so it looks more crowded in there than it is. The swinging tree limb is the one shaped like a "V". They climb up and down all the time.
A group of the Tinys on the stationary branch, and some of the girls on top of the run. There's one chicken on the swing on the right.
The dust bath (ready for a change in dirt, I must say!) and the hollow log behind it. You can see some of the Tinys inside, as well.