Freeze-drying and air-drying both remove water without cooking. Freeze-drying does it by freezing the food and drawing the ice off under vacuum, which leaves the structure intact and lets water go back in quickly.
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Against frozen raw: comparable ingredients, none of the logistics. No freezer drawer, no overnight thaw, no planning ahead. The trade-off is that you add the moisture back yourself instead of it coming with the food.
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Against dry kibble: kibble is cooked at high temperature and needs starch to hold its shape, which is why a bag lasts as long as it does. Freeze-dried has neither, so portions look markedly smaller for the same nutrition.
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Against wet or canned: a tin delivers moisture built in. Rehydrated freeze-dried arrives at a similar place, with the difference that you control how much water goes in — useful for a cat who needs more.
For cats specifically, that last point does more work than it might for a dog. Cats have a weak thirst drive and don't compensate well by drinking, so how a diet delivers water is worth thinking about rather than assuming.