Hollow Bully Sticks and Pizzle Sheath: What's Actually Inside a Bully Stick
Posted by Greg C. on Jul 14, 2026
Topic: Hollow Bully Sticks · Pizzle Sheath · Bully Stick Anatomy
You pick up a bully stick, look down its end, and find a hole running straight through the middle. Is that a defect? A safety problem? Something you should return? The honest answer is that hollowness is the natural consequence of what a bully stick actually is — but it changes what you paid for and how the chew behaves in its final ten minutes. Here is what is inside a bully stick, why some are hollow, and most are not, what "pizzle sheath" really means, and what to do about it.
What a bully stick is actually made of
A bully stick is a single ingredient: dried beef pizzle. But pizzle is not one uniform material. It is a structure with three distinct parts, and every question about hollowness traces back to that structure.
The sheath. A tough fibrous outer casing — the tunica albuginea. This is what gives a bully stick its skin-like exterior and most of its tensile strength.
The core. Dense, spongy erectile tissue: the corpus cavernosa. This is the bulk of the chew, and it is what makes a bully stick heavy and long-lasting.
The channel. Running down the center is the urethral canal. It is cleaned out during processing, leaving a void.
What happens to that void is the entire story. During processing, the pizzle is cleaned, stretched, and twisted before it is dried. That stretching and twisting collapse the channel, and as the tissue dehydrates around it, the walls press together and fuse into a dense, solid rod. That is a normal bully stick, which is why most sticks you buy have no hole at all.
But the channel does not always close. If a pizzle is unusually thick-walled, if it is dried faster than it is stretched, or if a producer skips the twisting step to move product faster, the void survives dehydration. What you end up holding is a stick with an open tube down the middle — a hollow bully stick.
The short version: A hollow bully stick is not contaminated, is not a different ingredient, and is not inherently dangerous. It is the same beef pizzle as a solid stick. What it is is less of it — and that has real consequences for value and for how the chew fails at the end of a session.
Why hollowness costs you money
Nearly every brand on the market sells bully sticks by length. Six-inch. Twelve-inch. That is the number on the bag, and that is the number people shop by.
Length tells you almost nothing about how much chew is in your hand.
Two twelve-inch sticks can sit side by side on a shelf and look nearly identical. One is dense all the way through. The other has a channel running its full length. Same price, same label, same shelf — and meaningfully different amounts of actual beef inside. Your dog does not chew inches. Your dog chews mass.
This is exactly why we grade and sell our bully sticks by weight, not by appearance. The ladder runs Standard, Select, Supreme, Monster, Beyond Monster, and those grades are weight bands, not looks. A stick that photographs big but weighs light does not get to be called a Monster here. It is the single most important thing a bully stick buyer can understand, and hollowness is the clearest possible illustration of why it matters.
| Structure | Mass per inch | Chew time | How it fails | Best for |
|---|---|---|---|---|
| Hollow stick | Low — a tube around the air | Shortest for its size | Splits lengthwise, thins to a ring | Stuffing, if you accept the tradeoffs |
| 12" Select Odor-Free — Medium Thickness | High — dense through the core | The reliable default | Frays and shortens evenly | Most medium dogs |
| 12" Monster Jurassic — XL Thickness | Highest in the lineup | Longest single-stick session | Frays slowly, stays thick to the end | Power chewers, large breeds |
| 12" Braided Bully Sticks | High — three strands | Roughly double a single stick | Unravels strand by strand | Dogs that finish sticks too fast |
| 4–5" Curly Springs Odor-Free | Moderate | Short, high-engagement | Breaks into curl segments | Small dogs, portioned sessions |
Is a hollow bully stick safe?
Lower risk than most chews on the shelf — but not zero risk, and the risks are different from those of a solid stick. Three mechanisms are worth understanding.
Tubes split. Rods fray.
A solid bully stick softens and frays as a dog works it. The fibers separate into soft, digestible strands, and the end of the stick becomes more of a brush than a blade. A hollow stick has a thin wall wrapped around a void, so instead of fraying inward, it tends to crack lengthwise, opening into a curved sheet with a firmer edge. That edge is still fully digestible beef, not a rawhide-style shard — but it is less forgiving on the gums than the frayed end of a solid stick.
The jaw-trap geometry
A wide, hollow-ended can occasionally catches a small dog's lower jaw or tongue inside the cavity. This is the same failure mode that is well documented in hollow cow hooves, and we covered the mechanism in detail in "bully sticks vs cow hooves". It is far less common with pizzle, because pizzle is softer and yields under pressure, whereas a hoof is rigid and will not. But the geometry that creates the risk is the same, and it is worth knowing it exists rather than being surprised by it.
The stub window arrives sooner
Every bully stick ends the same way — as a short piece small enough to swallow whole. With a hollow stick, the wall thins out faster, leaving a lightweight ring rather than a solid nub. The swallowable stage arrives earlier in the session than the starting size would suggest. Take the stub to 2 to 3 inches, every single time. That one habit is the largest safety lever any chew owner has, and it matters more with a hollow stick than with a dense one.
Honest about the risk, not scared of it. Bully sticks are fully digestible and do not splinter the way rawhide does, which puts them in the lower-risk tier of long-lasting chews. Lower risk is no risk. Supervise every session, remove the stub, and if your dog has a history of GI obstruction, gulping, or resource guarding, talk to your veterinarian before adding any long-lasting chew — this one included. If a piece does go down whole, here is what actually happens next.
Pizzle sheath: the other half of the question
"Pizzle sheath" gets used loosely, and two different meanings are worth separating.
As a layer, the sheath is the fibrous outer casing on every bully stick you have ever bought. It is not an additive or a coating. It is anatomy, and it is already part of what you are feeding.
As a product, some manufacturers separate the sheath out and use it on its own — most often wrapped around a beef cheek roll to build a two-material chew. Sheath-only chews are thinner, more translucent, and chew faster. They are closer in feel to a wrapped chew than to a bully stick, and they carry a distinct trap: because the sheath is thin and flexible, some dogs peel and swallow strips of it whole rather than chewing them down.
One thing pizzle sheath is emphatically not is rawhide. Rawhide is the inner layer of cattle hide, chemically processed, and it digests poorly enough that a swallowed piece can swell and lodge. Pizzle sheath is muscle and connective tissue from the pizzle itself, with the same digestibility profile as the rest of the stick. The two look somewhat alike and behave nothing alike. The full breakdown is in bully sticks vs rawhide.
"But I want a hollow one — I want to stuff it"
This is the one genuinely good reason to want a hollow bully stick, and it deserves a straight answer rather than a dismissal.
The appeal is real. A hollow tube takes peanut butter or a lick paste, goes in the freezer, and turns a twenty-minute chew into a forty-minute enrichment session. Veterinarians and behaviorists lean on frozen stuffed chews constantly — for crate training, for separation work, for post-surgical dogs who cannot burn energy any other way.
But the stick does not have to be hollow for you to get that. A solid stick smeared with a spreadable and frozen material delivers the same slow-lick engagement without the split-tube edge or the jaw-trap geometry. Better still, put a dense stick inside a purpose-built stuffable holder — you get the enrichment, the stick stays a chew, and the hollow-specific failure modes never enter the picture at all.
Two caveats if you go the spread-and-freeze route. Read the peanut butter label for xylitol, which is toxic to dogs and turns up in "no sugar added" brands. And count the calories: a stuffed chew is a chew plus a snack, and it adds up faster than most owners expect.
What to buy instead
If a hollow stick is a tube of air, the Monster Jurassic is its exact opposite — the heaviest-weight grade in the lineup, dense throughout its entire cross-section, with no channel to run out early. This is the direct answer for anyone who has been burned buying big-looking sticks that finished fast. You are not buying inches here. You are buying by graded weight, and the chew duration corresponds to the weight.
Braiding is the structural answer to the same problem hollowness creates. Three strands twisted together force the dog to rotate and reposition constantly, rather than drive straight down one axis, which stretches the session out. The textured surface adds to dental scraping. If your dog has graduated past standard thickness and you want more chew without moving to the heaviest grade, this is the step.
The Select is where most dogs belong. Dense throughout the core, odor-free, and priced based on what it actually weighs rather than how big it appears in photos. If you came to this article because a stick you bought elsewhere turned out to be hollow, this is the straightforward replacement — same length, considerably more beef.
Small dogs are where hollowness bites hardest — a lighter stick disappears faster, and a small dog's jaw is the one that can get caught in a wide hollow end. The 6" Select gives you a genuinely dense chew scaled down to jaw size and calorie budget, and it is the right starter for a dog being introduced to bully sticks for the first time.
| If this is you | Buy this | Why |
|---|---|---|
| My stick was hollow and finished too fast | 12" Monster Jurassic — XL | Heaviest graded weight, solid through the core |
| My dog destroys any single stick | 12" Braided | The three-strand structure roughly doubles the session |
| I just want the reliable everyday stick | 12" Select — Medium | Dense core, odor-free, weight-graded |
| Small dog, puppy, or calorie control | 6" Select — Medium | Full density, scaled to jaw size |
| I want a short, high-engagement shape | 4–5" Curly Springs | Coiled cut, portioned session, odor-free |
| I want to see every grade side by side | Full Bully Stick Lineup | Standard → Select → Supreme → Monster → Beyond Monster |
Frequently Asked Questions
Because the urethral channel that runs through a bull pizzle did not fully collapse during drying. When a pizzle is properly stretched and twisted before dehydration, the channel closes, and the tissue fuses into a solid rod. When that step is rushed or skipped, the void survives. It is a processing outcome, not a contamination issue.
They are the same single ingredient with the same digestibility as any bully stick, which puts them in the lower-risk tier of long-lasting chews. The differences are mechanical: hollow sticks tend to split lengthwise rather than fray, a wide hollow end can occasionally trap a small dog's lower jaw, and they thin out to a swallowable ring sooner than a solid stick does. Supervise the session and remove the stub to 2 to 3 inches. Lower risk is no risk.
It is not a safety defect. It is arguably a value defect. A hollow stick contains less beef than a solid stick of the same length, so if you paid by the inch, you paid for air. That is the entire argument for buying bully sticks by graded weight rather than by length.
No. Chew duration tracks mass, not length. A hollow twelve-inch stick has less material than a dense twelve-inch stick, so your dog will get through it faster. That is the practical consequence in one sentence.
You can, and it is the one legitimate reason to seek a hollow stick out. But a solid stick smeared and frozen, or a dense stick placed inside a stuffable holder, delivers the same slow-lick enrichment without the split-tube edge or the jaw-trap geometry. If you do use peanut butter, confirm the label is free of xylitol, which is toxic to dogs and appears in many "no sugar added" brands.
No. Pizzle sheath is the fibrous outer layer of the pizzle itself — muscle and connective tissue, fully digestible. Rawhide is the inner layer of cattle hide, chemically processed, and digestible enough that swallowed pieces can swell and cause obstructions. They look somewhat alike and behave nothing alike.
The urethral canal runs through the pizzle and is cleaned out during processing. What remains is the channel it left behind, which normally collapses during drying. The finished product is beef pizzle and nothing else — one ingredient, no additives.
Buy by weight rather than by length. A brand that grades its sticks into weight bands tells you how much beef is in the package; a brand that only publishes inches does not. Our lineup is sorted: Standard, Select, Supreme, Monster, Beyond Monster — those are weight grades, and they are the reason a Monster is a Monster.
