Another opinion on this is that I would only worm if I knew that my chickens had worms....would you take antibiotics if you didn't have an infection?? Sevin dust kills the honey bees I wouldn't touch that stuff unless you had to ! There are enough chemicals in our food and environment and part of the reason I raise chickens for eggs is so I know what I am consuming. Everyone has a different take on this some think that this is a preventative measure,,,Not me I have 7 three yr old chickens that give me around 5 eggs a day and I have never had mites and only used herbs to prevent worms. I would recommend regular checks for mites and then treat if you have an infestation... if you suspect worms take a sample to a vet to know for sure. just my opinion... Either way enjoy your chickens they are so much fun