I picked up a bottle of Wazine-17 wormer at the feed store today and I have a question. It says on the bottle "for each 100 birds, use 2 fluid ounces of Wazine-17 in 2 U.S. gallons of drinking water." Let's say I'm worming a single hen. Am I supposed to still use 2 fl of the wormer or do I have to use less?