The only way to properly diagnose is to have a fecal float test done. You will only see worms in droppings if the bird is so infested the larger worms (usually roundworms) get forced out. You will need a dewormer like Safeguard, natural remedies like DE, ACV and raw pumpkin seeds do not work as a preventative or a dewormer. Cocciadosis is usually found in younger birds and would require Corid to treat.
Thanks, will followChickens can get roundworms, cecal worms, capillary worms, more rare worms such as gapeworms, tapeworms, and the rarer, eyeworms. Fecal floats by a vet can be helpful to identify which worm larvae that is present. Not all vets will do those. Valbazen sheep and cattle wormer is excellent for most worms. Fenbendazole. (SafeGuard Liquid Goat Wormer or Equine paste) is also very good to use against many worms. For tapeworms, a product with praziquantel, is the best choice. Equimax or Zimectrin Gold are good just for tapeworms. Her is some reading about the different worms, but I do not recommend using ivermectin for worms, since it has lost some effectiveness: