I have about 20 Bantams and it started with one of my roosters sneezing. Now I am hearing the the rest of them sneeze as well but other than they seem allright. I called our vet (he will give phone advice thats about it for chickens) and he told me to buy Sulmet for their drinking water. I also have Terramycin at the house, BUT..... I am reading here that alot of people use Tylan. What would be best and how much per gallon would I use??