Egg cannibalism or not?


In the Brooder
11 Years
Sep 22, 2008
For a few weeks now, when I have gone to collect eggs from the laying box, I have been finding eggs with holes broken into them, with most of the contents of the broken eggs still present inside (that is mostly uneaten).
The size of the holes is typically the size of a quarter (but not circular like a quarter), and sometimes bigger.

The laying box is accessible to potential egg predators (principally squirrels, wild birds, cats), as my birds are out to range free during the daytime.

Even though I do feed egg shells (from the kitchen) to my hens, which my hens eat voraciously and completely, nevertheless I'm not suspecting one of the hens yet because I also find the shell fragments in the nesting box next to the broken eggs. I'm thinking that if one of the hens were indeed breaking the eggs, then its principal goal would be to eat the shells (which my hens love to eat) and no shell fragments would remain in the nesting box as they in fact do. By the way, in the past I have fed (empty) half-shells to my hens - but since the trouble started I've been breaking the shells into fragments before feeding them to the hens.

By the way - for completeness:
More often than not there are only two eggs in the laying box per day (from my three hens), whereas sometimes there are three. I know one of the hens used to lay in (hard to find) places in the undergrowth under hedgerows. I write that here because several months ago now I found a broken egg on the roof of my car in the street outside the fence and on the opposite side of my house to the side where my birds are.

My question to experienced keepers is: Does this pattern of egg breakage (which I described at the beginning of this posting) suggest any particular type of egg predator?


In the Brooder
11 Years
Sep 22, 2008
Do the hens have access to any other significant source of calcium?

As my birds range freely every day, I think they get their calcium mostly from grit in the soil.
One of the three hens always produces medium-sized brown eggs with good strong shells.
Another hen has produces large white eggs with wrinkly shells ever since she started a year ago - sometimes more wrinkly, sometimes less - with OK thickness shells.
The third hen produces large white eggs with OK thickness shells - she's the one that might be laying her eggs somewhere other than the nesting box most days.
The hens are all just under 2 years old, and they're pearl white leghorns.

Also, apart from what insects/grubs they catch in the garden, they eat the following grain and seed, with which I feed them when I put them in the coop before sunset:
- 2/3 cup millet per bird,
- 1/3 cup black sunflower seeds per bird,
both of which contain calcium, though not in huge quantities.

I wonder why you ask about calcium, as the pieces of shell broken from the shells are not being eaten, but left adjacent to the broken eggs.​
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10 Years
May 31, 2009
It's difficult for chickens to get enough calcium from soil which is why it's good to give them supplemental calcium. Many people recommend baking egg shells and then feeding them back so that the chickens are "fooled" into thinking that it's not their eggs and won't eat the eggs. I use Manna Pro oyster shell. I just bought a new bag after a year at $6.99 and I changed it out every couple of weeks.

I have a concern over their diet in that I don't think they're getting enough protein and other vital nutrients with the limited items. Often times chickens eat their eggs because of a nutritional deficiency. You don't say how large your yard is but after an initial couple of weeks, it's common for a yard to have its insect population reduced by the chickens so there's not as much to eat. I have six chickens, 1/10th of an acre for them to roam and I still feed chicken feed; Purina Flock Raiser which is 20% protein. It's in a feeder for them to free feed when they wish. I go through a 50 pound bag about every two and a half months in the summer, more in the winter and I change it out frequently.

Chicken feed is a much more complete food and has more protein than than millet and BOSS. Typical layer feed already has calcium added and is usually around 16% protein, other feeds vary from this to a higher amount.

If I had to guess, I would say that it's your chickens eating the eggs. Perhaps, they're leaving shells and stuff because they're full. I'm not sure the wild birds have the wherewithall to break the shells and eat the eggs, wild cats are a possibility and I'm not sure about squirrels.

Do you have golf balls or other enticers in the nest to encourage them to lay there? Is it possible to collect the eggs more frequently? This might help out. But try giving them some chicken feed. They'll still eat the bugs and grass from free-ranging.

Good luck, Mary

These are some suggestions.

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