I have a couple of questions about deworming: for how long does the dewormer act in their system? (Just for the day you give it to them or a couple dayside longer?) and how long do you typically see the worms in their stool as the dewormer is working? Should they be gone from stools in a few days?
Wormers start to work right away. Certain types of worms may require continued worming for 5 days straight, it depends what wormer is used and what types of worms are being treated. You may or may not see worms in feces after worming. Most of the time they are digested as protein. Once birds are wormed, you should see health improvement anywhere from several hours to several days.
I prefer a "shotgun" approach when worming...using a broad spectrum wormer. It saves time and money rather than taking fecal samples to a vet every three months for testing.