RI? How? Why? seriously confused

[WingedWolfPsion]

TBH, this sounds like something contagious, and not a rack ventilation problem--you have 3 animals down with it in the same rack? Be sure that you disinfect the upper surfaces of the rack shelves--vinegar is not much of a disinfectant, you will need to use something that will kill bacteria and viruses, like bleach solution or F-10.

Double check the temperatures in that rack. One year, I had part of a heat cord fail--the top part worked, the last few feet did not, leaving one shelf without heating.

In your place, I would instate a very strict quarantine. Sick animals would be removed from the room, and the rack they were in would be separated from the others. Wash hands in between handling or changing water on EVERY animal (hand sanitizer is, sadly, not sufficient--latex gloves are also good). Do the 'sick' rack last when you go through the room, and the sick animals after that--never transfer anything between bins or racks, and keep each animal in its own bin, without switching bins or shelves.

Observe animals that are being treated carefully--if they do not progress as they should, tell the vet immediately. Remember that it's almost always possible to culture something, and an opportunistic bacterial infection is not always the primary cause of an illness. (In other words, if you start antibiotics, the animals shows some minor improvement, but then doesn't get progressively better, it may still be a virus).

It's better to be too paranoid, than not enough. I hope your critters get well quickly for you!