You have to eliminate the source of tapeworm infections which are insects. Insects are the host for tapeworms. Do your best to control insects. Keep in mind that not all insects are hosts for tapeworms. Perhaps you can give your birds Albendazole along with Praziquantel to eliminate tapeworms. Albendazole is used to treat human tapeworm infections. It may or may not treat poultry tapeworms. Here, it has lost its effectiveness treating tapeworms. Praziquantel is the drug of choice to eliminate tapeworms in addition to eliminating the source; insects.
It also sounds like you also have a respiratory disease in your flock, possibly Mycoplasma Gallisepticum (MG).
I recommend that you close your flock, no new birds in, none out. Do not sell nor give birds away and dont bring new birds into your flock. The disease can be passed through eggs. No selling nor giving away eggs to be hatched. You must close your flock. Eggs are safe to eat. MG is very contagious.
Tylosin treats MG, but doesnt cure the disease. Depending on the strain (mild or deadly), surviving birds will be carriers for life.