food grade diatomaceous earth will not kill the tape worms in infested birds, it is used mainly as preventive..
best to worm with proper wormer to be sure you rid your birds of the worms and use diatomaceous after the worming to "possibly" prevent re infestation,
but i personally don't rely on food grade diatomaceous alone.
One thing, if you want try an experiment, if you know or think your birds have worms, collect some droppings for one to three days, and then have the vet perform the fecal parasite examination on those stools, then after having that done and it is shown that your birds do in fact have worms.
Then try diatomaceous earth and after at least 14 days of the birds ingesting it(diatomaceous earth), take another batch of stool samples back to the vet and see if worms are still present, you will be surprised to more than likely still find that your birds still have worms..
Goldenseal may work if you know how to use it, but I'm unsure of how to make a tonic or what exact amount to use. still looking for more information on goldenseal and its proper use for poultry..
Anthelmintics: Introduction
http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/191500.htm
Drugs Acting on Adult Tapeworm Infections in Birds
In the poultry industry the meat production has increased continuously worldwide (cf. Coccidiocidal Drugs/Economic Importance). In 1994, the annual meat production amounted to ~13 million tons in the USA, ~6.1 million tons in China, and 628.000 tons in Germany. In birds, losses due to moderate and seldom heavier tapeworm infections may be diarrhea (enteritis), weight depression, emaciation, and rarely mortality. Free-range birds, e.g., those in backyard flocks, and cage birds in aviaries with earthen floors are often hosts to many species of tapeworms (e.g., Davainea proglottina, Raillietina spp., Cotugnia spp., Amoebotaenia cuneata, Choanotaenia infundibulum, Hymenolepis spp., Fimbriaria spp., and other cestodes). Their life cycles require the development of cysticercoids (larval stages) in a large number of intermediate hosts such as various copepods, snails and insects. Modern husbandry methods may largely prevent access to the various intermediate hosts, thus preventing tapeworm infections in commercial poultry. Consequently, only little information is available about adequately tested compounds in birds. Niclosamide (250 mg/kg, per os) seems to be effective and safe in most cases (can be toxic to geese). Praziquantel (510 mg/kg) is effective against a wide range of immature and mature cestodes in poultry, waterbirds (ducks, geese) and game birds (pheasant, partridge). However, an economic return to its use seems to be questionable. Benzimidazole carbamates (fenbendazole, mebendazole, other compounds, Nematocidal Drugs, Animals), exhibit variable actions on avian cestodes. Fenbendazole is somewhat erratically effective against Davainea proglottina, and the activity of mebendazole is limited to Raillietina and Hymenolepis.
Old Remedies and Modern Compounds with Cestocidal Activity
There are many old remedies showing more or less activity against adult tapeworms. Thus pumpkinseeds, powdered areca (fruits of betel palm, Areca catechu), kousso (flowers of an Abyssinian tree, Hagenia abyssinica), turpentine (oily mixture of exsudates from coniferous trees, especially longleaf pine), pomegranate root bark (tropical Asian and African tree, Punica granatum), and male fern (Dryopteris filix-mas) were used as anticestodal remedies. These and other plant products had been gradually replaced by arecoline (alkaloid obtained from seeds of betel palm), organic tin compounds, lead arsenate or dichlorophen(e) during the first half of this century. Since 1921, arecoline has been used in veterinary medicine for many years against Echinococcus granulosus and Taenia spp. in dogs. Because of its relative low efficacy and its severe side effects, it is no longer recommended as a therapeutic drug in dogs and cats. However, its strong parasympathomimetic action causes purging and thus partial removal of paralyzed worms from the intestine. This action makes arecoline a useful diagnostic agent, which may give valuable information on whether a group of dogs on a farm is infected with Taenia spp. or Echinococcus spp. or not.