The problem with waiting is that it can be very difficult to detect when they have worms, unless you wait until they have such a heavy load that they start showing up in the poop or until the birds start looking poorly and their health declines. You can have fecal tests done but if you go that route you have to do them routinely and often because it's very easy to get false negative tests if the worms just don't happen to be shedding eggs when a test is done. Fecal's can also cost a lot depending on where you have them done, my avian vet charges $50.00 a pop, not something I'm going to do on a regular basis lol! Worms are very damaging and it's far better for the birds to stay on top of the worm population by keeping them on a regular schedule based on your climate and the parasite load. Where I live it's hot/dry for much of the year so I deworm twice a year.
