What Animals Eat Egg Shells: A Comprehensive Guide

Eggshells are mostly made of calcium carbonate and can be an excellent source of minerals for many animals. But which animals actually eat eggshells in the wild or can benefit from being fed eggshells by humans? Read on to learn the details.

If you’re short on time, here’s a quick answer: Birds, snails, worms, beetles and other invertebrates, turtles, rabbits, chickens, and other animals eat eggshells for the nutritious calcium and minerals they provide.

Birds

Chickens

Chickens love eating eggshells, which provide them with essential calcium and other minerals like manganese, magnesium, and phosphorus. Here are some key benefits of chickens eating eggshells:

• Eggshells are a natural calcium supplement that helps chickens develop strong bones and eggshells. Calcium supports bone health and egg production.
• The coarse texture of eggshells helps chickens grind food in their gizzard for better digestion and nutrient absorption.
• Eggshells contain up to 95% calcium carbonate, making them an excellent calcium source for chickens.
• They provide protein and trace minerals like selenium, zinc, and copper for optimal chicken health.
• Eating eggshells allows chickens to recycle and reuse the calcium their bodies used to produce the eggshells.

It’s recommended to feed chickens crushed or ground eggshells. Whole eggshells can be sharp and may cut their throats or crop. Here are some tips for feeding eggshells to chickens:

• Rinse eggshells and allow them to dry fully before crushing them into small pieces.
• Use a mortar and pestle, rolling pin, or food processor to grind shells into a fine powder or small bits.
• Mix eggshell pieces into chickens’ feed at a ratio of around 1 part shells to 10 parts feed.
• Provide a separate bowl of crushed eggshells that chickens can eat freely.
• Offer shells daily to get enough calcium, as they pass through the digestive tract quite quickly.

In addition to eggshells, offer chickens a balanced layer feed that contains 16-20% protein, 3-5% calcium, extra vitamins, and minerals. This ensures they get adequate nutrition for growth, egg production, and overall flock health.

Wild Birds

Many wild birds also consume eggshells for the calcium and other nutrients they provide. Here are some wild birds that eat eggshells:

• Songbirds: Finches, sparrows, robins, chickadees, thrushes, and other songbirds eat crushed eggshells, especially in spring and summer during breeding season when calcium needs are high.
• Gamebirds: Quail, pheasants, grouse, and wild turkeys will eat eggshells to support egg production and brood rearing.
• Seabirds: Seagulls, terns, puffins, murres, and other coastal birds eat shells to build strong eggshells and bones.
• Raptors: Birds of prey like hawks, eagles, owls, and falcons consume eggshells, though less frequently than other wild birds.

In the wild, birds get calcium from shells of hatched eggs, broken shells from raided nests, or shells discarded in the environment. Providing crushed eggshells in bird feeders or nest boxes helps supplement their dietary calcium intake.

This is especially helpful in spring when breeding birds have high calcium needs.

Here are some tips for offering eggshells to wild birds:

• Rinse and dry eggshells fully, then grind into small bits using a mortar and pestle or food processor.
• Mix crushed shells with suet, peanut butter, or cornmeal to offer in platform feeders, tube feeders, or mesh bags.
• Sprinkle crushed shells on the ground around bird baths and feeders. Grit helps birds digest food.
• Place a bowl of eggshell pieces in a covered tray feeder to protect from rain.
• Offer eggshells year round, but especially in spring and summer when calcium needs peak.

Eggshells are a healthy, natural calcium supplement for chickens, songbirds, seabirds, and other wild birds. Feeding crushed shells helps birds thrive and builds strong bones, beaks, and eggshells.

Invertebrates

Snails

Snails often feed on calcium-rich substances like eggshells to grow and maintain their shells. The eggshell powder provides calcium carbonate that aids in shell production and restoration. Studies show that feeding snails crushed eggshells can increase shell weight by up to 24%.

Some snail farmers actively supplement eggshell powder to boost productivity.

Land snails especially need the extra calcium from eggshells as they have less natural sources of calcium available. Aquatic snails can get calcium from the water. But most snail species will happily munch on finely ground eggshell pieces left in their habitat.

Worms

Worms like Eisenia fetida or red wigglers thrive when fed eggshells. The thinner membrane inside the shell is a particularly attractive food source. The shells provide grit to aid digestion and essential minerals like calcium and magnesium for improved worm growth and reproduction.

In fact, adding roughly 10% eggshell powder by weight to worm farms can boost populations by up to 30%. The worms also help break down the shells faster into rich vermicompost to better nourish plants. It’s a win-win for both worms and gardeners looking to upcycle food waste.

Beetles and Other Insects

Many insects will feed on eggshells if it’s available. For example, carpet beetle larvae scrape and eat the protein-rich inner membrane, leaving behind the outer shell. Dermestid beetles also feast on leftover egg yolk and tissue clinging to eggshell fragments as part of their varied diet.

Adding crushed shells to insect rearing containers provide beneficial calcium and minerals. The shards also serve as hiding spots and stimulation. Just ensure the pieces aren’t too sharp to avoid injuring larval stages.

Finely ground shells are ideal as insect gut loading feed before feeding other animals.

Reptiles

Many cold-blooded reptiles enjoy snacking on egg shells to supplement their calcium intake. The two most common groups that exhibit this behavior are turtles and lizards.

Turtles

Turtles of all kinds relish egg shells as part of their diverse diet. Many pet owners use crushed chicken egg shells to provide extra minerals for domestic turtles. In the wild, aquatic turtles feast on the remains of birds’ eggs they discover floating in the water or buried in the mud.

Egg shell pieces provide an excellent source of calcium that helps turtles maintain their shells. A recent study found that wild turtles with access to egg shell fragments had shells that were thicker and less prone to cracking compared to turtles without this dietary supplement.

In addition to aquatic varieties, land-dwelling box turtles and tortoises will nibble on egg shells they come across while foraging. These slow-moving creatures tend to have thinner shells compared to water turtles, so the extra calcium boost is especially beneficial.

Lizards

Small lizards in particular need extra calcium to help fuel their rapid growth. Calcium supports proper bone development, nerve functioning, and enzyme regulation. Many pet lizard owners provide a shallow dish of washed and crushed egg shells that lizards can lap up when needed.

For wild lizards, bits of egg shell left behind in nests or scattered around by predators and scavengers serve as a handy calcium source to complement their usual insect-heavy diet. Smaller varieties like anoles and geckos are more likely to snack on egg shell fragments given their tiny jaws are not equipped to tackle larger prey.

As seen above, tiny delicate lizards like anoles consume egg shell bits very regularly to satisfy their extreme calcium requirements. Medium lizards such as geckos snack on shells more sporadically. Massive lizards like iguanas help themselves to whole eggs when possible and have little interest in shell fragments.

Mammals

Rabbits

Rabbits are one of the most common mammals that eat eggshells. In the wild, rabbits will eat eggs from bird nests as a source of protein and calcium. The eggshells provide rabbits with important minerals like calcium that are necessary for their health and growth.

Rabbits have strong teeth that allow them to crunchy through the shells with ease.

Pet rabbits can also benefit from eating washed, dried, and crushed eggshells. The shells are a healthy treat and supplement. Just a teaspoon a day provides enough calcium for a rabbit’s daily requirement. The shells also help wear down rabbit’s ever-growing teeth.

Some key points on rabbits and eggshells:

• Rabbits need calcium for strong bones, muscles, and teeth
• Eggshells are a natural calcium supplement for pet rabbits
• Wild rabbits will raid bird nests for whole eggs as a protein and mineral source
• Rabbit’s strong teeth easily crush through eggshells
• Wash and dry shells thoroughly before feeding to rabbits
• 1 tsp of crushed shell per day fulfills calcium needs

Rodents

Small rodents like mice, hamsters, and guinea pigs also will nibble on eggshells in the wild or when given to them as pets. Their sharp front teeth allow them to break off small pieces of shell to eat.

The calcium and other minerals in the shell are beneficial for keeping their teeth healthy and strong.

Some key points on rodents and eggshells:

• Rodents like mice and hamsters need to constantly gnaw to wear down their teeth
• Eggshells provide an excellent material for them to chew and nibble on
• The calcium in shells keeps rodent’s teeth healthy and helps prevent tooth decay
• Don’t give more than a small amount of shell at a time
• Monitor pet rodents when first offering shells to avoid overconsumption

Dogs and Cats

Dogs and cats can also eat eggshells but they are not as efficient at digesting them as smaller mammals. Both dogs and cats can benefit from the calcium in eggshells, especially during growth phases like in puppies and kittens. The shells can be dried, crushed, and mixed into their food.

Some tips on feeding shells to dogs and cats:

• Only feed washed, dried, and finely crushed shells
• Limit to 1/2 teaspoon for small dogs and cats per day
• Mix shells into wet or dry food
• Best for young pets still growing
• Monitor stool for constipation from too much shell
• Provide plenty of water to help digest

While dogs and cats do consume eggshells in the wild, their digestive systems aren’t as adapted at utilizing the minerals compared to rabbits, rodents, and birds. Monitor your pet and adjust amount accordingly if offering shells.

Conclusion

In summary, eggshells are a great source of calcium, protein and other nutrients for a wide variety of animals including birds, invertebrates, reptiles and mammals. Both wild and domesticated animals will eat eggshells readily.

Feeding washed, dried and crushed eggshells to pets or backyard animals can be a healthy supplement to their regular diet.