Then I wouldn't worry about worms unless you are seeing weight loss. I know some like to worm their chickens yearly or more often, but I've kept chickens for almost 15 years and wormed with a wormer twice - once the whole flock and once a single hen.
Boost their immune system with garlic...
I've never used garlic powder and not sure if it would be good. You can always get rid of the garlic powder by dumping some into their feed.
I use a cut up garlic clove (just sliced in half) in the waterers as it is antiviral.
Never had a problem with eggs tasting garlicky.
Are you...