garlic and pumpkin/squash seeds are also helpful for worms. oregano is a good health boost. there has been good research about using oil of oregano in feed as an alternative to constant antibiotics in commercial broiler flocks. It's a nice immune booster, I add to to the bucket once a week. there's an excellent article on herbs and their uses for chickens here: http://naturalchickenkeeping.blogspot.com/2013/05/herbs-and-their-uses-for-your-chickens.html