All of my chickens are under a year old. I have 6 Silkies, 1 Wyandotte, and 1 Ameraucana. I wormed all of them for the first time about 10 days ago with Wazine. I didn't see any worms in their poops. Their run area is on the ground, and they do come out daily in our grass and plant areas, where they eat grass, worms and bugs. With me not seeing any worms in their poops, is it really necessary to worm them again with a product like Valbazen or Safeguard? I want to do what's best for all of them, but I'm wondering if it would be overkill (and hard on their bodies) to worm them again with either Valbazen or Safeguard when I didn't see any worms. And what is everyone's preference -- the Valbazen or the Safeguard? Any input would be greatly appreciated.