What are bully sticks made of?
A study published in the Canadian Veterinary Journal found that only 44% of dog owners could correctly identify what bully sticks are made of, and neither could 38% of veterinarians. The answer is beef pizzle: a single muscle, one animal part, no blends. Below: where it comes from, why dogs are drawn to it, how it is processed, and the red flags to check before you buy.
This guide covers what bully sticks are made of, where they are sourced, and how they are manufactured, for US dog owners. For safety specifically, see the bully stick safety guide.
Part of the Ultimate Bully Sticks Guide. See also: which bully sticks are the safest.
What are bully sticks made of?
Bully sticks are made of beef pizzle. That is the polite term for the penis muscle of a bull. One ingredient, one animal part: no grains, no binding agents, no mystery meat blends.
The tissue is dense muscle, which is why the protein content is unusually high (80 to 97% crude protein depending on processing method) and the fat content is low. Beef pizzle is tough, fibrous, and naturally chewy. Because the muscle is so dense, the resulting chew lasts longer than most treats while still breaking down fully in the stomach. Unlike cooked bones, bully sticks do not splinter. Unlike rawhide, they digest safely.
You will see beef pizzle on ingredient labels, so it helps to know the word. It comes from the Low German pesel or Dutch pees, meaning sinew, and has been used in English since the 15th century. Other names for bully sticks: pizzle sticks, beef sticks, bull pizzles. All the same product.
Why are they called bully sticks?
They are called bully sticks because of the source animal and the shape: bull, plus stick. The name is descriptive, not a brand term, which is why every manufacturer uses it.
The treat itself is older than the modern name. Pizzle has been processed into durable goods for centuries, well before it became a packaged dog chew. The exact origin of the bully stick as a retail pet product is not clearly documented, but it emerged the same way most natural chews did: as a practical use for a part of the animal that the meat industry would otherwise discard. Turning that byproduct into a single-ingredient chew is what makes bully sticks a more sustainable option than treats that require dedicated farming.
Where do bully sticks come from?
Bully sticks come from cattle raised for beef production. The pizzle is a byproduct of the meat industry: if it were not made into dog chews, it would be discarded.
But not all sourcing is equal, and where the cattle were raised affects the final chew. Because cattle raised on open pasture build denser muscle tissue, the resulting bully stick tends to be tougher and last longer, and it can carry higher Omega-3 levels, more conjugated linoleic acid (CLA), and more vitamins A, D, E, and K than grain-fed feedlot cattle.
The questions to ask about any bully stick brand: were the cattle grass-fed or grain-fed? Were they given growth hormones or routine antibiotics? Was the slaughter process humane and regulated? Does the manufacturer control the supply chain, or buy from whoever is cheapest?
How bully sticks are made
The manufacturing process is what separates a safe, nutritious bully stick from one that is cheap, chemically treated, and potentially contaminated. Two sticks can look identical on the shelf and be completely different products underneath.
Here is how Natural Farm makes bully sticks, entirely in-house. If you find a chew that works for your dog, you can set up recurring delivery through Subscribe & Save and adjust the cadence as your dog's preferences change.
Bully stick nutritional profile
Because a bully stick is a single ingredient, the nutritional profile is straightforward, with no fillers diluting the numbers.
| Treat | Protein | Fat | Calories (6 inch) |
|---|---|---|---|
| Standard bully stick | ~93% | ~3% | ~88 |
| Cold-Dried | Up to 97% | ~1% | ~65 |
| Pig ears | ~60% | ~30% | ~130 |
| Rawhide | ~80% | ~1% | ~40 |
Numbers vary by stick size, thickness, and processing method. Rawhide is low in fat but poses digestibility and chemical processing risks.
The fat difference is significant: pig ears contain roughly 10 times more fat than a standard bully stick. For dogs on calorie-restricted or low-fat diets, that distinction matters. Fat percentage on its own is not a weight-management metric, so always factor in total calories alongside it.
Natural Farm Cold-Dried bully sticks push the profile further: up to 97% crude protein and around 1% fat. The proprietary low-temperature drying preserves more of the natural protein structure, producing a denser beef chew. For a full comparison of all types, see the best bully sticks for dogs ranked by size.
Are bully sticks safe?
Yes, bully sticks are generally one of the safest long-lasting digestible dog chews available. They do not splinter, and they contain a single natural ingredient with no chemicals or preservatives. The one rule: always supervise, and remove the last 2 to 3 inches to prevent choking. That small end piece is the only real risk.
Safety depends almost entirely on sourcing and processing. A stick from grass-fed cattle, manufactured in a USDA-inspected facility, and third-party tested for pathogens is a different product from one imported from an unregulated facility with no testing. The ingredient is the same. The safety profile is not.
For more detail, see the full bully stick safety guide and whether puppies can have bully sticks.
Bully sticks vs rawhide
They look similar on the shelf, but bully sticks and rawhide are fundamentally different products.
| Criteria | Bully stick | Rawhide |
|---|---|---|
| Ingredient source | Beef muscle (pizzle) | Animal skin (hide) |
| Digestibility | Fully digestible | Not fully digestible |
| Chemical processing | None (water only) | Often uses lye, hydrogen peroxide |
| Splinter risk | Minimal | Can splinter and shard |
| Blockage risk | Low (remove at 2 to 3 inches) | Higher; can require surgery |
| Notable recall history | No major US chemical-contamination recalls | 2018 multi-brand recall for chemical contamination |
The recall history is the clearest illustration of the processing gap. In 2018, a major manufacturer voluntarily recalled multiple rawhide brands across the US after a quaternary ammonium compound, an antimicrobial chemical not approved as a processing aid for dog chews, was identified in production. Bully sticks made with water-only cleaning do not carry that category of risk. Natural Farm Power Chews, a long-lasting beef chew made from pizzle and beef cheek, won the Pet Innovation Awards 2023 Rawhide Alternative of the Year. For a complete safety comparison, read which bully sticks are the safest.
What to look for when buying
Six checks separate a quality bully stick from a risky one. Use this as a buying checklist.
| What to check | Why it matters | Red flag |
|---|---|---|
| Ingredient | Should be 100% beef, nothing else | "Made with real beef" |
| Sourcing | Grass-fed tends to be denser, higher in Omega-3 | No origin disclosed |
| Facility | USDA inspection means regulated safety oversight | No facility info |
| Testing | Third-party testing means independent verification | No testing claims |
| Odor process | Natural drying means no masking chemicals | "Smoke flavored" |
| Price | Quality has a cost; safety is not free | Rock-bottom pricing |
Natural Farm meets all six criteria and publishes its FDA facility registration publicly. It has been rated Best Overall bully stick by The Spruce Pets for five consecutive years.
Why dogs love bully sticks
Dogs and wolves eat organ and muscle meat first after a kill because it is the most nutrient-dense part of the animal. Beef pizzle triggers that same instinctual draw: the natural aroma signals high-value protein, and the flavor intensifies as the stick softens.
The texture sits in the sweet spot between hard enough to satisfy the chewing urge and soft enough to break down gradually. Because sustained chewing releases endorphins, a bully stick session tends to leave dogs calmer and less destructive. It is not just a treat: it is mental stimulation.
Explore the bully stick guide series
This guide is one part of a larger cluster. Start with the Ultimate Bully Sticks Guide for the full overview, then check whether bully sticks are safe for dogs and whether puppies can have bully sticks. To choose a specific product, browse the Natural Farm bully sticks collection, compare options in the best bully sticks ranked by size guide, or try the premium Natural Farm Cold-Dried bully sticks. For long-lasting chewers, the Natural Farm Power Chews collection is worth a look.
Frequently asked questions
What are bully sticks made of?
Bully sticks are made of beef pizzle, the penis muscle of a bull. Natural Farm bully sticks use 100% grass-fed beef with no additives, chemicals, or preservatives, cleaned with water and slow-dried.
Why are they called bully sticks?
They are called bully sticks because of the source animal and the shape: bull, plus stick. Other names include pizzle sticks, beef sticks, and bull pizzles, all the same product.
Who invented bully sticks?
No single inventor is documented. Bully sticks emerged as a practical use for beef pizzle, a part of the animal the meat industry would otherwise discard. The product is the byproduct of beef production, turned into a single-ingredient chew.
Are bully sticks just bull penises?
Yes. Beef pizzle is 80 to 97% protein, fully digestible, and one of the cleanest single-ingredient dog chews available. Natural Farm bully sticks are cleaned with water only, with no processing chemicals.
Do bully sticks smell?
Cheap ones can. Natural Farm reduces odor through extended drying and proprietary preparation, not chemicals or smoke flavoring. Natural Farm bully sticks are odor-free by default.
What is Natural Farm Cold-Dried made of, and how is it different?
Natural Farm Cold-Dried bully sticks are made of the same single-ingredient beef pizzle as the classic. The difference is the proprietary low-temperature drying, which preserves more protein structure: up to 97% crude protein and around 1% fat. It is an evolution of the classic bully stick, not a replacement for it.
How does Subscribe & Save work for Natural Farm bully sticks?
Subscribe & Save sets up recurring delivery of your chosen bully stick at a discount, with the flexibility to skip or cancel any time. Many owners standardize on one size and cadence once they find a match, so they do not run out mid-week.
How fast is shipping for Natural Farm bully sticks?
Every order ships through Amazon. Prime members get free shipping, always. Not Prime? Amazon still delivers, with free shipping on orders $79 and up.
Why buy bully sticks from Natural Farm
- 100% grass-fed
- Single ingredient
- Odor-free
- In-house manufacturing
- Third-party tested
Founded in 2018. Natural Farm owns its USDA-inspected, FDA-registered facility, with a single supplier and full traceability. Every order ships through Amazon: Prime members get free shipping, always, and non-Prime orders ship free at $79 and up.
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