A friend of mine has a small flock of chickens that have developed a respiratory issue with the sudden cold, wet weather. I told her she could pick up some Tetracycline(now labeled Duramycin) for them but the package only has MG measurements and i can't find a good conversion online. How much of the powder should she mix with their water? and for how long? She has Gallon size waterers and her problem was she couldn't find a tsp/tbsp, "everyday" measurement for the medicine.