Until I get a bird showing signs of worms and a fecal sample back from a vet that says they are positive for x type of worm, I won't be giving any poisons to kill x worms to the fluffy butts. It's hard on their systems and anything done too often, even drinking too much water, can kill. Been over 10 years and haven't had the need so far so I'll just keep on going. However, this is another issue of ask 10 people get 20 answers on what to do. In the end it is up to you.