Three of my boys have rats. Two of them we've had for a little over a year and the other one we got a week ago from Petco. When we got the two a year ago, one of them was sick with Mycoplasma. We started her on some Zythromax, treated her for 14 days with it and she got better! Well, this new rat has introduced the Mycoplasma junk (at least that's what I'm thinking it is) back into the rat house and the one who was initially sick and cured is sick again. This time it is worse. She was sneezing so badly that her nose started bleeding and started to sneeze blood. I have put her and the new rat back on Zythromax 5 days ago and the bleeding has stopped, but the sneezing won't go away. I read this morning on a rat health site that terramycin is effective in treating the Mycoplasma. Does anyone know what dosage I need? When my chickens first got sick I used the terramycin in their waterers and am wondering if I could mix some and pour it into the rat waterer. Please help! These ratties are so loved and my boys would be so devastated if we lost them.