Isn't really a cage that is "too big" for the snake, after all when they are in the wild they aren't born in shoeboxes. You just need to add that much more to the enclosure to make them feel safe. However this can prove challenging if you have a hatchling corn in a 5' cage
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Then the snake would be too larger for the keeper
Another type of wood (in addition to all softwoods) that should be avoided is walnut. Walnut trees are very toxic
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.