Do Chicks Care About Calcium? Or is it about companies and outdated studies

[CabritaChicks]

People love to debate calcium and salt content in a chicken’s diet. Some claim that too much calcium for young birds is dangerous, but have you ever stopped to question where that idea comes from?

I live in a place where feral chickens rule the land—quite literally. Toss a stone, and you’ll probably hit one (not that you should). These birds thrive on the sea, not just near it, but on the coral reef itself. Not sandy Florida beaches—actual reef. And guess what? They multiply like cockroaches, and we watch them grow up, and they are healthy.

The idea that too much calcium is harmful to young chickens has been around since at least the 1960s, with studies showing that excess calcium could reduce growth, disrupt nutrient absorption, and cause mineral imbalances (I do not dispute that!). Research from the '90s reinforced this, linking high calcium intake to issues like hypercalcemia and poor performance in broilers.

But here’s the thing—my findings don’t line up with this narrative. Feral chickens in my area thrive while pecking at coral and shells, with no signs of these supposed calcium-related issues. It makes me wonder: Are these studies overlooking the bigger picture of a natural, varied diet? Or is the problem more about artificial feed formulations rather than calcium itself?

Now, let’s be fair—calcium can be bad. Too much, in isolation, can cause kidney damage or mess with a bird’s ability to process other nutrients. But here’s the thing: calcium is just one piece of the puzzle. Saying "young chickens shouldn’t get calcium" is like saying humans should eat more avocados. Sure, avocados are great, but they’re still just fat. You don’t live on just fat, and chickens don’t live on just calcium. Their diet is a whole recipe, and nature has been mixing that recipe long before we started overanalyzing it.

So when I hear warnings about "excess calcium harming young chickens," I can't help but raise an eyebrow. These birds peck at shells, coral, and whatever else nature provides, and they seem just fine. So I dug deeper. As a scientist, I wanted real answers. And what did I find? Many of those "calcium overload" studies are backed by pet food companies—the same industry that once force-fed Purina dog food to canines (and let’s be real, that’s not exactly gourmet nutrition).

The real issue? A bad diet makes the perfect storm. If a chick is already on an imbalanced, artificial diet, then yes, adding too much of one thing—like calcium—could cause problems. But personally, I think the sooner they get used to their natural environment, the better. Feral chicks don’t get some carefully measured calcium supplement—they get whatever nature hands them, and they’re thriving.

So, is calcium really the villain? Or is this another case of corporate-driven misinformation?

What do you think?
.... not here to start an argument, just a conversation as I am interested.

BTW, these are some of the studies I was specifically looking at:

• Maxwell, M.H., Robertson, G.W., and Mitchell, M.A. In 1993, they published a study titled "Ultrastructural demonstration of mitochondrial calcium overload in myocardial cells from broiler chickens with ascites and induced hypoxia," examining calcium deposits in heart cells of broilers under hypoxic conditions. AGRIS+1AGRIS+1
• Shafey, T.M. Also in 1993, Shafey authored "Calcium tolerance of growing chickens: effect of ratio of dietary calcium to available phosphorus," exploring how excess calcium intake affects growth, feed efficiency, and bone strength in growing chickens. Cambridge University Press & Assessment+1NCBI+1
• Sebaei, M.G.E., El-Shafei, R.A., El-Adl, M.A., Farag, A., and Eladl, A.H. In 2020, they conducted a study titled "Biochemical and molecular investigation of oxidative stress associated with urolithiasis induced by increased dietary calcium or protein in chickens," evaluating the impact of high dietary calcium or protein levels on various health parameters in chickens. PubMed
• Honarbakhsh, S., Zaghari, M., and Sang, B. Their research, "Effect of excessive calcium feeding on health of gastrointestinal tract in broiler breeder hens," investigated the impact of high calcium diets on the gastrointestinal health of broiler breeder hens. Brill

 

[nuthatched]

The glaring difference being the matter of choice.
Nonlaying birds such chicks, pullets, molting/broody hens and males shouldn't eat high calcium layer feed since there's no where for the calcium to go as opposed to egg laying females.
There's a big difference between pecking at coral as needed and have relatively high levels of calcium forced into Every. Single. Bite.

another case of corporate-driven misinformation?

Hmm, honey.
If you don't like corporate-funded research, you're going to find limit options on peer reviewed papers.
Most corpate entities do fund research for their own benefit. Does that make the research wrong? No.
The majority of poultry research is short term [less than 2 years] because meat and egg companies don't keep birds longer than that.
If the consensus among scientific papers, the knowledge of Veterinarians (who's purpose is to keep the animal healthy) and the experience of your little ol' backyard keeper all indicate that a diet of no-choice high calcium diet to a non-laying bird is harmful to their long term health, then it better to error of the side of caution and provide them with calcium they can take if they need.
For some birds, the daily high calcium is better, such as for high production birds.

Poultry Science is the most researched area of Agriculture on the planet, you can pick any country you wish for research.

I'm just going to point out that your local feral chickens are likely more akin to a jungle fowl at this point, probably pretty lanky, alert, slim and sporty, can fly fairly well, less production per hen, than your average backyard hen.

 

[U_Stormcrow]

People love to debate calcium and salt content in a chicken’s diet. Some claim that too much calcium for young birds is dangerous, but have you ever stopped to question where that idea comes from?

I live in a place where feral chickens rule the land—quite literally. Toss a stone, and you’ll probably hit one (not that you should). These birds thrive on the sea, not just near it, but on the coral reef itself. Not sandy Florida beaches—actual reef. And guess what? They multiply like cockroaches, and we watch them grow up, and they are healthy.

The idea that too much calcium is harmful to young chickens has been around since at least the 1960s, with studies showing that excess calcium could reduce growth, disrupt nutrient absorption, and cause mineral imbalances (I do not dispute that!). Research from the '90s reinforced this, linking high calcium intake to issues like hypercalcemia and poor performance in broilers.

But here’s the thing—my findings don’t line up with this narrative. Feral chickens in my area thrive while pecking at coral and shells, with no signs of these supposed calcium-related issues. It makes me wonder: Are these studies overlooking the bigger picture of a natural, varied diet? Or is the problem more about artificial feed formulations rather than calcium itself?

Now, let’s be fair—calcium can be bad. Too much, in isolation, can cause kidney damage or mess with a bird’s ability to process other nutrients. But here’s the thing: calcium is just one piece of the puzzle. Saying "young chickens shouldn’t get calcium" is like saying humans should eat more avocados. Sure, avocados are great, but they’re still just fat. You don’t live on just fat, and chickens don’t live on just calcium. Their diet is a whole recipe, and nature has been mixing that recipe long before we started overanalyzing it.

So when I hear warnings about "excess calcium harming young chickens," I can't help but raise an eyebrow. These birds peck at shells, coral, and whatever else nature provides, and they seem just fine. So I dug deeper. As a scientist, I wanted real answers. And what did I find? Many of those "calcium overload" studies are backed by pet food companies—the same industry that once force-fed Purina dog food to canines (and let’s be real, that’s not exactly gourmet nutrition).

The real issue? A bad diet makes the perfect storm. If a chick is already on an imbalanced, artificial diet, then yes, adding too much of one thing—like calcium—could cause problems. But personally, I think the sooner they get used to their natural environment, the better. Feral chicks don’t get some carefully measured calcium supplement—they get whatever nature hands them, and they’re thriving.

So, is calcium really the villain? Or is this another case of corporate-driven misinformation?

What do you think?
.... not here to start an argument, just a conversation as I am interested.

BTW, these are some of the studies I was specifically looking at:

• Maxwell, M.H., Robertson, G.W., and Mitchell, M.A. In 1993, they published a study titled "Ultrastructural demonstration of mitochondrial calcium overload in myocardial cells from broiler chickens with ascites and induced hypoxia," examining calcium deposits in heart cells of broilers under hypoxic conditions. AGRIS+1AGRIS+1
• Shafey, T.M. Also in 1993, Shafey authored "Calcium tolerance of growing chickens: effect of ratio of dietary calcium to available phosphorus," exploring how excess calcium intake affects growth, feed efficiency, and bone strength in growing chickens. Cambridge University Press & Assessment+1NCBI+1
• Sebaei, M.G.E., El-Shafei, R.A., El-Adl, M.A., Farag, A., and Eladl, A.H. In 2020, they conducted a study titled "Biochemical and molecular investigation of oxidative stress associated with urolithiasis induced by increased dietary calcium or protein in chickens," evaluating the impact of high dietary calcium or protein levels on various health parameters in chickens. PubMed
• Honarbakhsh, S., Zaghari, M., and Sang, B. Their research, "Effect of excessive calcium feeding on health of gastrointestinal tract in broiler breeder hens," investigated the impact of high calcium diets on the gastrointestinal health of broiler breeder hens. Brill

I think you've drawn improper inference from your anecdote, and need to read more studies. Maybe give some consideration to control of variables, as well..

There is a marked difference between a free range bird self-regulating calcium intake (as in your anecdote, and the experience of all of us who offer oyster shell or another calcium source in separate dish) and birds whose calcium intake is directly determined by the quantity of their homogenized feed intake. And there are studies to back our experience an anecdotes.

Birds eating a homogenized feed will eat to meet their dietary energy needs as their first priority - even if that means eating an excess of calcium. Numerous health consequences can result. Most pronounced in very young birds (as are most other nutritional deficiencies), but also time and dose dependent.

To the extent your comment above might suggest that the calcium needs of hatchlings and prime production hens during their laying periods are similar, I'd suggest you rethink that assumption, which is implicit in your suggestion.

but if you would like to fund your own research for publication (here or elsewhere), please do. As your peers, we'd be happy to review.