I have a "food saver" vacuum storage system. Best investment I ever made. With no air in the bag, you can freeze for years and they will not freezer burn and stay fresh as the day you froze it.

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When I was able to buy mice in bulk, I'd vacuum seal portions that were enough to feed all my snakes without having to open the entire stock allowing air and freezer burn occur.

Great for humans too, of course. I can now buy mass quantities of meat on sale, portion them up and vacuum seal it. I never have to worry about pulling out a roast or steak that is a year or two old. It will still be fresh and free of freezer burn.

By far, the best method is vacuum sealing and storing at around 0 degrees F.

Other than that, freezing silversides in water does help keep the air from getting to them and keeps freezer burn away. Not sure how that would work with pinkies.