Make sure their run has plenty of space -- a minimum of 10 square feet per bird -- and make sure their run has plenty of "clutter" to give them the opportunity to do chicken things.
This thread has loads of information on that:
https://www.backyardchickens.com/threads/a-cluttered-run.1323792/
Here are a few specific suggestions:
https://www.backyardchickens.com/articles/blocks-bricks-and-pavers-the-critical-chicken-keeping-equipment-the-“chickens-101”-articles-don’t-mention.76003/
Other good chicken entertainment options include a straw bale with one tie cut for them to tear apart, a big pile of leaves raked out of your yard, or all the non-toxic weeds from your garden.
This is my run:
View attachment 2826366
I agree.
And when I do food as entertainment I make them work for it -- putting into a pile of pine straw or throwing greenery into different piles in different parts of the pen.