Pumpkin seeds/yogurt/buttermilk are more worm preventatives. They will keep alot of worms at bay, but are not necessarily foolproof. The seeds can be whole or chopped up or some of each. Some birds may not eat them, though. One of my hens for seme reason does not eat them-when I feed her scratch with pumpkin seeds, even chopped, she picks around them, so obviously, they won't do her any good. From time to time, you should probably look at their fresh poop to see if you can see any worms. Naturally, you wont be able to see the worm eggs, if there are any.