One of my hens is having respiratory issues - I was given oxytetracycline in the 4+ ounce packet of powder by the feed store, who also has hens and uses this. I have no clue how to dose - all it says on the outside is that it makes 512 gallons at the 200mg concentration, 256 gallons at the 400mg concentration, etc. I asked the feed store lady and she says that she puts a teaspoon in one gallon of water when she treats her hens! That seems like a high concentration based on the label??? Or am I doing the math wrong??