We just got new rats (although have had them in the past), 15 weeks old, and sneezing. Could be just the new environment but made an appointment with vet for Wednesday anyway. In the meantime, I make homemade Elderberry syrup for my family for cold and flu season as it's a good immune booster, as well as antimicrobial, antifungal, antibacterial, antiviral, etc, and I know it's safe for my dogs as well, just not sure about the rats. Ingredients are: Water, Honey, Elderberries, ginger, cloves, sage, and thyme (in order of amounts). All ingredients except the honey are cooked, berries mashed, then strained and only juice is used. I really think this might help quite a bit but not exactly certain all ingredients are safe for rats. Any thoughts would be greatly appreciated!! Many thanks!