Segments to me mean tape worms, they shed segments that wriggle and squirm on their own.
I am not sure the best de-wormer to use in chickens, but what works on other worms doesn't work on tapeworms in dogs, cats and horses.
You need something specific for tapes.
If the Zimecterin Gold that is used in horses, is safe with chickens, it will take out tape worms. It has an ivermectin base, but the "gold" is added specifically as an anti tape worm medication
(praziquantel). I know ivermectin can be given to chickens, but I don't know about the praziquantel. Maybe someone here can help with that?
I also know in horses, Strongid (pyrantyl) can be given triple dosed to control tapes in horses, but I don't know in chickens. It also controls other parasites, like roundworms in the standard dose.
As you can see, I have more experience with horses. I hope this helps, maybe someone with more chicken savvy can help clarify this. I hope I didn't confuse things.