I'm not sure where you heard kiln dried does not help with the oils as that's the only kind of pine that IS okay to use.

Many people will still avoid it for pets just in case, I think and to spoil their pets, but pine is cheaper than aspen so it is more economical for breeding large numbers of rodents.

Some lines of rats or mice may be more sensistive, I think, but they seem to be less healthy animals overall from what I have read or it isn't the pine oils causing an issue, but rather a dusty brand/source of the bedding.

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