Depends on where you're shipping them to. Obviously, freezing is a very real concern. Heat packs can be used to help prevent this, but a lot will depend on the shipping method--overnight vrs 2 day, etc. And, of course--where they are going to matters. If the recipient won't be able to sign for it, or pick it up immediately, packages may end up sitting on their front step for hours--increasing the odds of a problem.