One of our hens is sneezing and her eyes are swollen shut, seems to be a respitory infection. We went to Tractor Supply and got antibiotic powder that is supposed to be mixed in their water. The powder is 10 grams. The instructions call for 200 to 400 milligrams per gallon of water. We're trying to figure out how to measure that out since we don't have a food scale (never mind one that measures in mgs) and conversion calculators are absolutely no help. Any thoughts? Thanks!