Do you have any pictures? Valbazen can treat tapeworms, but praziquantel, the active ingredient in Equimax horse paste will treat them best.
@dawg53 is a good person to help with that. Equimax dosage is 0.03 ml per pound, or 0.15 ml for a 5 pound chicken. Zimectrin Gold also has praziquantel, but the dosage is different. I think Dawg53 recommends multiple doses of Valbazen for tapes. There are many intermediate hosts for tapeworms, such as snails and slugs, beetles and darkling beetles, flies, and earthworms which eat the tapeworm larvae in the droppings, so keeping those away from chickens can help to keep from getting reinfested.