Chicken hearts and gizzards are lean, protein-dense parts that most owners file under organ meat and most nutritionists do not. Both are muscle. A heart is cardiac muscle that never stops working, and a gizzard is the thick muscular grinding chamber of a bird's stomach. That distinction is not pedantry, because it changes how much of each belongs in a bowl and what else the diet still needs. Hearts are among the best natural sources of taurine and coenzyme Q10, gizzards bring collagen and a great deal of protein for very few calories, and neither one substitutes for liver.
What they actually are
The heart is a hollow pump built from cardiac muscle. It contracts continuously from before birth until death, so its tissue is unusually dense in mitochondria, the structures that generate energy inside cells. Trimmed chicken hearts are small, firm and lean, with a modest fat cap that trimming removes.
The gizzard is stranger. Birds have no teeth, so food passes into a muscular chamber where powerful walls grind it against swallowed grit. Those walls are thick, dense smooth muscle with a tough inner lining that is peeled away during processing. What remains is very lean muscle laced with connective tissue, which is why gizzards stay chewy no matter how you cook them.
Why the muscle versus organ distinction matters
Ratio feeding systems divide a diet into muscle meat, bone and secreting organs, and they cap secreting organs at roughly ten percent of the whole because those organs are so concentrated in vitamin A and copper. Heart and gizzard do not secrete anything. They are working muscle, and they count toward the muscle meat portion.
Get this backwards and the diet drifts. Counting hearts as organ meat means the diet ends up short on the vitamin A and copper that liver was supposed to provide. Counting liver as muscle meat means overshooting those same nutrients badly. In a formulated recipe none of this falls to the owner, because the formulator has assigned every ingredient to its proper category already.
What they contribute nutritionally
Heart is the more interesting of the two. It carries taurine in amounts few other foods match, plus coenzyme Q10, vitamin B12, iron, zinc, phosphorus and complete protein. Dogs, unlike cats, can synthesise taurine from the sulfur amino acids methionine and cysteine, so taurine is not classed as essential for them in the same way. Even so, taurine status varies with diet composition, body size and individual metabolism, and dietary sources contribute. Heart is a whole-food one.
Gizzard is leaner still and heavy on protein for its calorie count. The connective tissue running through it supplies collagen, and the meat itself carries zinc, selenium, iron, phosphorus and B vitamins. Its texture is the practical selling point. Dogs who bolt soft food have to actually chew a gizzard.
Where they fit in a bowl
Inside a complete recipe, hearts and gizzards work as part of the muscle meat base, contributing protein and micronutrients that plain breast meat does not. The My Perfect Pet Chicken and Beef recipe is an example of a formulation that builds these parts into a finished, balanced meal rather than leaving the ratios to guesswork.
Outside a complete recipe, they are toppers and treats. Cooked plain, cut small, no seasoning. Treats and toppers share one allowance, ten percent of the day's calories, and heart and gizzard both draw from it.
Cautions
Introduce either one gradually. Both are rich in a way that shows up as loose stool when a dog goes from none to a bowlful in a day. A few small pieces, then wait, then a few more.
Whole gizzards are dense and chewy enough that a determined gulper can try to swallow one intact. Cut them down for small dogs and for any dog who eats without pausing.
Seasoning is the usual hidden problem with parts bought from a butcher counter or used in a household recipe. Onion and garlic are common in the pan and are not appropriate for dogs in any quantity.
Here is the one that matters most. If a veterinarian has raised any concern about your dog's heart, that is a cardiology conversation, and diet changes belong inside it rather than ahead of it. Taurine status is assessed with a blood test, not inferred from a shopping list, and feeding hearts is not a substitute for a diagnostic workup or for prescribed medication. Loop in your vet before organ or muscle-meat additions become routine, particularly for a dog on a therapeutic diet.
Call a veterinarian the same day for laboured breathing, coughing at rest, fainting, a swollen abdomen, sudden exercise intolerance, repeated vomiting or blood in stool.
For general grounding, the AAFCO consumer guide explains what a complete and balanced claim covers, and the AKC nutrition library is a solid owner-level reference.
Frequently asked questions
Are chicken hearts organ meat?
No. Heart is muscle, specifically cardiac muscle, and ratio feeding systems count it toward the muscle meat portion. It does not replace liver or kidney in a diet.
Do gizzards count as organ meat either?
They do not. A gizzard is the muscular grinding section of a bird's stomach, so it is muscle meat with a lot of connective tissue running through it.
Should I feed hearts for taurine?
Heart is a genuine dietary taurine source, but feeding it is not a way to diagnose or manage a taurine concern. If taurine has come up regarding your dog, ask for the blood test rather than adjusting the bowl.
Raw or cooked hearts and gizzards?
Cooking removes bacterial risk for your dog and for everyone in the kitchen. Plain, unseasoned and cooked through is the straightforward option for most households.
How many can I give at once?
Fewer than you would guess. Start with one or two small pieces for a medium dog, keep all extras under a tenth of daily calories, and increase slowly if stools stay normal.