>>I was wondering who big a problem it was getting to be in general. If one of the baby snakes I picked up had round worms, it seems likely this guy entire collection is infected. As I recall all he was selling was corns. I have no concerns for my snakes, as I had them in quarentine, detected the pests, and treated them.

in general I don't think it's a problem....I've never had a snake with them, and many of the private keepers/breeders I know have been parasite free as well. I think it's just people with poor husbandry.
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Corn snakes and rat snakes...No one can have just one.
"Resistance is futile"
Jimmy Johnson
Draybars Snakes