Can Cats Eat Egg Shells?

Egg shells are not a good thing to feed your cat. None of the vet sources we read say shells are poisonous. They also do not say shells are helpful. A cat on complete cat food does not need them. If you think your cat needs more calcium, ask your vet before you add anything.

Why egg shells are not a good idea for cats

Cats on complete food usually have enough calcium

Shells are mostly sold as a way to add calcium. But the Merck Veterinary Manual says calcium and phosphorus shortages are uncommon in dogs and cats that eat complete and balanced food. Cornell’s Feline Health Center says foods with a “complete and balanced” label are meant to meet a cat’s nutrition needs.

Extra minerals can upset the balance

Merck warns against adding minerals without a reason, because it can cause a mineral imbalance. Calcium works together with phosphorus, and Merck says the balance between the two matters. A pinch of shell powder may sound harmless, but the sources we read do not say how much is right for a cat. We will not guess.

Cornell also says supplements can be harmful to cats and should never be given without a vet’s approval. Merck gives the same advice: no supplements unless your vet says so.

What about raw egg shells?

Shells from raw eggs may carry raw egg on them. The ASPCA says raw eggs can contain bacteria such as Salmonella and E. coli, which can be harmful to pets and people. The ASPCA also says raw eggs have an enzyme that can get in the way of some vitamins, which can lead to skin and coat problems. This is one more reason not to hand your cat a used shell.

Is it a problem if my cat already ate some?

The sources we read do not describe what happens when a cat eats egg shell, so we can’t promise either way. A small piece from a plain egg is not known to be a poison. Here is what to do:

• Watch your cat for a day or two.
• Call your vet if you see vomiting, diarrhea, or not wanting to eat.

What if I feed my cat a homemade diet?

This is the one case where calcium matters a lot. Merck says a diet that is mostly or all meat can be high in phosphorus and low in calcium. It also says signs of weak, soft bones (rickets) are most often seen when homemade diets are fed without the right supplements.

Merck says homemade diets are often missing key vitamins and minerals, and Cornell says they are hard to get right. If you want to feed home-prepared meals, talk to your vet, and ideally a veterinary nutritionist, first. Don’t make up your own recipe, and don’t use egg shell powder as your calcium plan.

What can I give my cat instead?

The easiest choice is a complete and balanced cat food. For a treat, Cornell says treats should be no more than 10 to 15 percent of your cat’s daily calories. A few bites of plain, fully cooked egg are one option, as covered in our guide to eggs for cats. For more on what to avoid, see foods that are toxic to cats.