Hello! Most likely the rice looking worms are segments of tape worms. If you have tried a conventional method of worming, and the worms are still there, I might recommend a natural worming method. The generally are a lot less toxic to the birds, more beneficial to them, and are better at keeping the worms away.
Pumpkin and pumpkin seeds are great dewormers for dogs, people, and chickens!! They absolutely love the pumpkin and the seeds. The can eat the seeds whole, but if you crack them open it will be more effective at getting the worms out. Rather than getting canned pumpkin or pumpkin seeds from the store, I recommend getting a whole pumpkin, cutting it open, and cracking some of the seeds for them- they can have it all. The pumpkin works by paralyzing the worms so that they come out of the intestinal tract when the chicken poops. This means most likely after giving them some, you will see in increase of worms in the poop until they are completely gone.
Other anti parasitic herbs you could use include oregano, and garlic. Braags apple cider vinegar is also highly recommended.
I know everyone has their own opinions about conventional vs. natural, but if you've tried the conventional method and aren't seeing the results you want, I definitely would try the pumpkin seeds if I were you.
Good luck!
Edit: Also, parsley. I highly recommend fresh parsley. A lot of chickens love it, and it is highly anti parasitic. I have never dewormed a chicken with it, but when my dogs had worms (a lot of worms) I pretty much completely got the worms out with parsley water and a puree of pumpkin and pumpkin seeds in their food.
And as far as the garlic goes, it is great for chickens with the right dosages (although too much of any good thing can be bad). However, if your hens are of laying age, the garlic might make their eggs taste like garlic!
