Who did confirm the diagnosis of rodents being the CULPRITS?!
Hippeastrums and other bulbs from the plant family of Amaryllids for example daffodils, are "deer and gopher proof" I am yet to raise any proof and evidence about the contrary!

The most ACUTELY-SUBSTANTIAL Predator of all parts of Hippeastrums that are protruding from the Soil, are big slugs (that these can even chew holes into the bulbs if not consume smaller bulbs entirely)

HOWEVER! It is a good idea to re-plant bulbs into plastic containers (these do not lose water through evaporation through the walls)

I do see the Big Slugs in the garden. I saw a rat hole and when dug up the bulb I saw a part of the bulb eaten. i am not sure if it was rodents or the slugs getting to the bulb using that hole. Thank you for the information. Will replant them soon.

I have to say, nothing is deer-proof. If it is a plant and isn't protected by fence etc, it can be eaten if the animal is desperate enough! I live in the country in Colorado and Nature can be pretty harsh here. If an animal is hungry enough, they'll eat it and they won't think twice.

You won't provide proof and evidence, that your assumption is accurate and correct, in the ammaryllogenous regard:
All parts of Amaryllids, contain derivates of Phenanthridine namely Amaryllidacean Alkaloids, and these are deadly poisonous, to MAMMALS. Particularly the bulbous parts contain these substances in high concentrations.

I am not sure if it was a rodent or a slug. There was a rodent hole next to the bulb. I dug up the bulb and saw a part close to the hole was eaten. I assumed it could be a rodent( being new into Hippeastrum ). After reading your reply I did check that there are huge slugs that come out during the night. Hence I thought it should be the slugs. I trust your expertise in this matter. I have replanted the bulbs and are they are looking happy now. Thank you for your assistance and advice :)