From time to time you may experience problems with your snails. Very little is known about what these illnesses are, what causes them, and even less is known about treatments. Unfortunately it seems more time is spent on increasingly more ingenious ways to kill them.
Because of this, the following information is a mix of whatever research is possible and available, theory and hypothesis, logical thinking and the result of various discussions with a large group of snail owners. It is with the help of the community at large, that these problems can at least be documented. Where possible I have tried to link to example incidents.
Hopefully, we can find some effective solutions to the majority of these problems but for now I'm afraid you'll have to be content with various suggestions and discussion.
Snails do not respirate a great deal but insufficient ventilation (especially during postage) will cause them to extend and go limp as clearly illustrated by the standard preservation practice of drowning snails in water, boiled to remove any oxygen. The snails are drowned as this causes them to die fully extended.
In normal snail keeping terms, this is an unusual problem and generally only mild ill-effects are suffered. Consequently, the snails can often recover.
Christabel, the owner of "The Snail Pages" (link now dead) experienced this problem when receiving some snails from myself and said:
"The signs of them being asphyxiated are that they are protruded right out from the shell but not responsive, usually with the eyes retracted. They're not attached to the sides of the container and the body is limp when you pick up the snail. If they are going to recover they should start to respond slightly within a few minutes of being given fresh air, and really perk up within a few hours."
Plenty of ventilation was provided so we surmised that the holes has been blocked by the outer packaging, in this case, polystyrene puffs. I'd tried too hard to make the package indestructible and as a result the puffs had been squashed into the holes on the internal container. You are most likely to witness the effects of asphyxiation when receiving snails so when packaging yourself, think carefully about how much air they have and make sure the holes you provide are not blocked.