Yep. They're foraging. By that stage, they're bored. They're probably also sporting around a lot, too.
My favorite thing to give in the litter is some instant oatmeal, scattered around. Its high in protein and they like it. A little ground CalfManna or finely ground scratch, a little bit of chopped grass or kale works, too. Not too much, though, since they dont have developed systems yet ad you dont want to mess up their feed balance. Just enough to keep them busy.
And make sure your top layers of litter are clean!
You might try a few bits of shiny or mirrored plastic or bright fabric, hung in the brooder. This gives them harmless things to peck at and keeps them entertained. Dont use things that will shred easily though, or they could get the shreds in their crops and clog up.