I tried a number of toys when I first got my chicks. They never really cared for anything I put in with them. So, I gave up on the toys idea.
What seems to work great for me is a pallet wood compost bin with the front panel cut down in half, and then taking that half of the pallet and putting it on top of the bin. The chickens love to sit on top of the bin and sun themselves on a warm day. If it gets too hot, they jump inside of the bin under the shade.
I had a big branch fall off a tree. Dear Wife and I dragged it into the chicken run, and they like to roost on that as well.
I let some wild junk trees grow in the run. They provide some shade for the chickens on a hot day. I just keep the tops clipped off because I have bird netting at 6 foot high.
I made a grazing frame where fresh grass grows in the run. They like to eat any blades sticking through the wire early in the morning before it's all gone. I might make a smaller grazing frame this year and plant something like barely, wheat, or oats in it.
The best thing for my chickens is that I converted my entire chicken run into a composting system. I dump all my leaves, weeds, grass clippings, old coop litter, and just about anything else organic into the run. The chicken run litter is full of tasty bugs and juicy worms. My hens spend most of the day scratching and pecking in the compost litter finding good things to eat, all the while making great compost for my gardens to feed my family. That's a real win-win in my book.
When the chickens have access to the chicken run compost litter in the non-snow months, my commercial feed bill is cut in half. I think a lot of that is due to them finding stuff to eat in the compost litter all day long.
They also dig holes in the compost for dust bathing. They do that a lot. I don't have any need for special dust bathing boxes or anything like that. They have some dust holes out in the full sun, and other dust holes under the shade.
I live on a lake, and we have hawks and bald eagles overhead all the time. So, I never let my chickens out of their run to free range in the yard. I'm sure they would like to free range on my property if it was safe for them. But I bring the free range to them with all the leaves, grass clippings, etc...
I think my chickens are happy. They are always busy scratching and pecking in the compost litter all day till they go back into the coop for the night. They have a good life full of chicken activities.