Recently (3 months ago) I lost a rat to pneumonia and after that experience I did everything in my power to protect my other girls. I bought a double critter nation (for 4 rats), set up an air purifier, got new dustless bedding( cat pellet paper), began to litter train, sewed fleece liners for each floor (washed 5 times before using /added absorbent towels underneath), sewed 10 new hammocks, and I pick up poop daily. However, one of my girls suddenly started showing symptoms of respiratory problems. She was acting perfectly fine and it has just started in the last ~12 hours with no previous indications that she would be sick. I'm confused about what this could be because it does not look like the typical Myco that I have seen before. There is no porphyrin around her nose/eyes, she is not sneezing, and she is acting relatively normal. The only symptom so far is a rough/crackly/wet sounding breathing that is coming from her upper airway and does not seem deep. She is not mouth breathing and it basically sounds like she has bad congestion/runny nose. I ordered Baytril and an evaporative humidifier yesterday as soon as I heard this... I also have doxycycline/ amoxicillin/ prednisone/ and azithromycin/ nebulizer from when our other girl was sick recently. Has anyone else had a similar experience or know what this could be? Also, do any of these meds sound like they could be useful right now? I want to treat ASAP because I have seen how fast they get bad. Thank you!