Are you certain it will be off shelves soon? I know that oral antibiotics will be prescription only after the end of this year 2016, but don't think wormers are included. Strike III is for use in the feed for at least 5 days to help control worms. It can be mixed 1 measure to a pound of feed, or mix the bag in 50 pounds of feed. Wormers such as Valbazen or SafeGuard liquid goat wormer can ne used to eliminate worms, and may be better choices and more accurate in dosage. Many vets will do a fecal float on a few fresh droppings to see if your chickens have worms. All chickens get worms if they are on dirt. There are many different opinions about worming chickens. Do some searching for making up your own mind.