Since it happened 2 months ago, in a different location, they've been moved since with different bedding and set up, I doubt anyone can tell you anything about what happened to the snakes.

Could you detail out a timeline of what happened when, including what set up and where the snakes were? Becuase it's very confusing when you said it just happened all at once, then over a few days, then two months ago, they were bloated but you weren't there and just found out....

So I think it's just confusing now, what happened when to how many.

If 5 snakes all died in a 2 day period, you were not there, with no access to the snakes and a non-experienced person was caring for them... my first guess would be a temp spike from a misplaced thermo-probe or a accidentally turned up thermostat.

Otherwise, you have no way to know if someone sprayed a room air freshener, or insect spray, or burned a candle, or tripped over the thermostat cord.... etc.