You know how some people are allergic to cats, or dogs but others are not? Maybe this is everyone's thought, those 3 out of 100 snakes are allergic to something in your house that the others are not. The more snakes you have the more chance there is for some to be allergic to something....maybe? It make sense to me because the Dr. where I work is allergic really bad to guinea pigs and no one else that works in the hospital is. So if it is possible to move these three, I would. Because it sounds like, medically, you are running out of options. Good luck with this though.
You bring up a valid point about the air fresheners and mold and etc and the like - but I would tend to not think this is an allergy thing simply because of :
1) I have hardwood floors
2) I don't use a febreze electrical outlet thing
3) The snake-room is isolated by heavy doors from the rest of the home.
4) The only chemicals I use in the snake room are 10% bleach and KY Jelly, if that even counts.
5) None of the other snakes have gotten ill AT ALL - any other species. The only sick snakes are Anery corn snakes. Maybe it's an anery thing? LoL
However, as I sit here writing this..I am thinking to myself..
Every single one of these snakes was housed, at one point or another, for an extended period of time in a 5 rack system i bought from the company HerpEnclosures about 5 years ago. I had two other large females in this rack and they are problem free, however, they were in and out of it and didn't spend a whole lot of time in there.
This rack system did malfunction at one point right after we moved into the new house and some of the interior material melted. Luckily, it was in a pan that no snake was in and it melted some of the plastic as well as the actual rack around the flexwatt and all so I just threw the whole pan out... Do you think it's possible that some of the vapors/chemicals released during this problem could still be present in that rack system and have caused harmful irritants to the snakes' lungs that are just now manifesting a year later?
ALL of these snakes started exhibiting their symptoms while present in this rack.
Wow. I never thought about this?