Not likely a large one would choke on it, as most likely they would break it into smaller pieces. But they don't need to be going crazy on it as if it's food or a treat. Specially if the diet is good.Yes, I would wonder if a large tortoise like an Aldabra might choke on the cuttlebone if given whole, so gratering it on his food is what I would do, also crushing the eggshells fine onto his food twice a week, or buying the reptile calcium powder.
Amazing. I'd have never thought of Tums. But they do have calcium.Egg shell is fine to use, just clean the egg out really well and grind it up. Tums also can be used. The easiest way is to scrape the cuttle bone onto their food 3 times a week or buy the powder calcium and use a pinch on the food 3 times a week.