Most worms are not seen in droppings without a microscope. The exceptions are large roundworms, and tapeworms which are rare in chickens. If you see the white things in the poop again, take a picture, and notice if they move. While I have seen light feed particles in my chicken’s droppings as well, tapeworm segments can look like moving rice in poop. They are treated differently with praziquantel. I am not saying those are what you are seeing. Here is a good video of tapeworm segments in chicken droppings:
