When Will Your American Bully Puppy Fill Out?

American Bully puppies undergo rapid growth. They start as adorable furballs, and seemingly, in the blink of an eye, they’ve transformed into fully-grown canines.

Knowing when your puppy will reach their full size is essential for ensuring that their growth is proceeding in a healthy manner. Typically, American Bully pups start filling out around 12 months. However, if you have a giant American Bully breed, their growth may continue until 18 to 24 months old. If your furry companion isn’t growing as expected, it’s advisable to consult with a veterinarian to identify any potential issues.

To ensure your puppy is on a healthy growth trajectory, it’s crucial to understand when they’ll reach their full size and have the right protection in place. Typically, American Bully pups start filling out around 12 months. However, if you have a giant American Bully breed, their growth may continue until 18 to 24 months old. Having the right pet insurance can provide peace of mind during this critical growth period.

In this post, we’ll examine the American Bully puppy growth cycle and offer tips for promoting a healthy development.

Table of Contents

When Will Your American Bully Puppy Fill Out? Understanding the Growth and Development

To protect your American Bully puppy’s well-being, it’s critical to understand the breed’s particular growth and development journey. This knowledge will enable you to determine whether your furry companion is progressing as planned or is experiencing growth-related difficulties.

Equally significant is the prevention of unchecked growth. A fundamental understanding of the growth pattern can aid in the prevention of health difficulties caused by ignorance or other reasons.

Furthermore, understanding your American Bully’s growth trajectory can alleviate concerns about why they haven’t reached their full potential yet. A fundamental understanding of the growth pattern can aid in the prevention of health difficulties caused by ignorance or other reasons.

American Bully dogs have muscular bodies that require a high protein diet, especially as they develop.
They also require appropriate calcium intake to promote the formation of strong bones.
Understanding these growth processes will allow you to offer your American Bully with the nourishment they require for health and vibrancy.

American Bully puppies generally complete their growth phase by the time they reach 12 months of age. However, the duration it takes for a Bully to reach its full size can vary, primarily based on size. Larger American Bullies may continue to add bone size and height, extending their growth period up to twenty-four months.

It’s essential to note that while there are average size projections for different American Bully classes, the actual size of individual dogs can vary. This variation is often influenced by each furry family member’s unique skeletal structure, which determines their ultimate height.

The long bones within American Bully puppies’ legs develop at their soft growth plates. These growth plates are crucial in building new bone structures, typically initiating the process gently and gradually stiffening as the puppy matures. The growth plates ultimately cease producing new tissue and become “closed” or calcified, indicating that the bone has reached its full size.

When Will Your American Bully Puppy Fill Out?

In terms of timelines, small-breed puppies usually reach maturity between 6 and 8 months of age, while Understanding these growth processes is crucial to providing your American Bully with the correct care and attention as they develop.

Factors Influencing Growth and Development in American Bully Dogs

American Bullies are susceptible to various health issues like many other dog breeds. It’s worth noting that Bully mix breeds are also susceptible to the illnesses outlined below. Here, we’ll explore some of the most prevalent health concerns that affect this breed:

Common Health Conditions Affecting American Bully Dogs

Being prepared for unexpected health issues is essential for every American Bully owner. That’s why having a reliable pet insurance plan can be a lifesaver.

Hip Dysplasia:

Hip dysplasia occurs when the hip joint develops improperly, leading to mobility issues in your dog.

Patellar Luxation:

This condition involves an abnormal development of the kneecap, which can dislocate and cause severe discomfort and lameness.

Cleft Lip

A cleft lip is a deformity affecting the mouth or upper lip.

Demodectic Mange

American Bullies, with their single coat, are susceptible to demodectic mange. Look out for signs like hair loss and scabs.

Hereditary Heart Failure

Also known as an “enlarged heart,” this condition can lead to fluid buildup in the body.


This skin disorder results in thicker paw pads and skin issues.


An allergy-related skin condition that can cause discomfort, especially in dogs with distinctive coat colours like the blue Bully.

Cerebellar Abiotrophy

This unusual condition affects the nervous system and the brain of the puppy.


Hypothyroidism can cause serious thyroid gland issues, impacting weight and activity levels.

Progressive Retinal Atrophy (PRA)

PRA gradually impairs a dog’s vision and can lead to blindness.


Vision loss is another eye problem that affects this breed and can be corrected surgically.

Knowing that these health conditions can influence your dog’s growth rate is essential. If your puppy’s growth significantly deviates from the average American Bully growth chart, consult your veterinarian for health assessments and guidance.

American Bully Growth Chart: What to Expect at Different Ages

How big will your American Bully puppy be as it grows? Here’s a handy chart that provides weight and height estimates at different stages of their development:

AgeWeight RangeHeight Range
3 months20 – 35 lbs8 – 10 inches
6 months50 – 70 lbs14 – 18 inches
1 year55 – 75 lbs16 – 20 inches

This chart provides useful information about your American Bully’s predicted size at various stages. However, it’s important to note that there are four distinct classes within the American Bully breed, each growing to different sizes and shapes in adulthood. These classes are Standard, Classic, Pocket, and XL American Bully.

When Will Your American Bully Puppy Fill Out?

Here’s a brief overview of American Bully growth by class:

  • Standard: These American Bullies typically fall within the average size range for the breed.
  • Classic: Classic Bullies tend to be more muscular and robust compared to other classes.
  • Pocket: Pocket Bullies are more minor in stature and are often more compact and stocky.
  • XL: XL American Bullies are known for their larger size and greater mass than other classes.

Understanding these class distinctions can help you predict how your American Bully will mature.

American Bully Types and Their Size Variations

Understanding the different classifications of American Bullies and their size distinctions is critical. Here’s a breakdown of the male and female size ranges for each American Bully type:

Type of American BullyMale SizeFemale Size
Standard BullyHeight: 17 to 20 InchesHeight: 16 to 19 Inches
Weight: 30 to 75 lbsWeight: 25 to 65 lbs
Classic BullyHeight: 17 to 20 InchesHeight: 16 to 19 Inches
Weight: 30 to 60 lbsWeight: 25 to 60 lbs
XL BullyHeight: 20 to 23 InchesHeight: 19 to 22 Inches
Weight: 74 to 130 lbsWeight: 74 to 130 lbs
Pocket BullyHeight: 14 to 17 InchesHeight: 13 to 16 Inches
Weight: 20 to 50 lbsWeight: 20 to 45 lbs

This table provides an organized overview of the size variations among American Bully types and genders.

When Will Your American Bully Puppy Reach Full Growth?

“Fill out” refers to when an American Bully puppy reaches its complete, natural size and weight as an adult dog. On average, you can expect your American Bully to fill out at around 12 months of age.

However, it’s important to note that the timing can vary among American Bullies. Larger breeds, like the XL American Bully, may continue growing for up to 24 months.

This growth process centres on the development of their bones at the soft growth plates. These growth plates initiate the formation of new bone tissues, starting out soft and gradually becoming more solid as your belly grows.

The growth plates stop producing new tissue and become calcified when the maximum bone size is achieved. Even though they are considered adults at 12 months old, puppies may continue to grow in terms of size, height, and bone development, which can extend anywhere from 6 to 24 months. Larger American Bullies, such as the XL variety, typically require about 24 months to reach full adulthood.

When Will Your American Bully Puppy Fill Out?

Maintaining a balance between your American Bully’s weight and size is essential. Keep in mind that there’s no one-size-fits-all ideal weight for this breed. Additionally, remember that dogs of the same breed may grow at different rates. It is vital to ensure that your Bully obtains sufficient nutrition and grows in a safe and supportive environment.


Your dog’s physical growth doesn’t always align with its mental development. As your puppy grows into an adult dog, a process known as “head-splitting” or “cracking” refers to the steady expansion of its head until it reaches full size.

It’s important to clarify that your dog’s head doesn’t actually “break” or “split,” as the terms may suggest. Instead, the size and form of the head fluctuate subtly. These changes might be gradual, making it easy for many dog owners to overlook them.

The pace at which this process unfolds can vary among individual dogs, mainly due to differences in skull thickness. Dogs with thinner skulls may experience a more extended timeline for their head muscles to mature and develop properly.

The head is one of the most distinguishing aspects of American Bullies, making it an important element of their growth. Around nine months, you might notice their head starting to split and expand, a transformation that continues until they reach 12 to 18 months. Remember that these changes are subtle and slow, and you might not immediately detect them as they occur.

When an American Bully reaches 12 months, they should begin gaining adult height and weight. It is crucial to remember, however, that some breeds may take longer to achieve full size, with some individuals growing for up to 2 or 3 years. Understanding this development process might help you appreciate your American Bully’s distinctive development.

Average Time Frame

In the following sections, we’ll explore how to assess if your Bully puppy is developing appropriately for its specific growth stage.

American Bully Puppies Under One Month

During this critical phase, American Bully puppies are at their most delicate stage of development. They are still growing and are completely reliant on their mother for warmth and sustenance. Puppies spend most of their time eating and sleeping at this stage. It’s essential to deworm them promptly, as they are susceptible to worm infestations during this period.

One-Month-Old American Bully Puppies

Your American Bully puppy will show signs of increased awareness at one month of age. Their eyes will open, and their ears will start functioning, allowing them to explore the world around them actively. Additionally, they will transition to consuming regular meals as their milk teeth begin to emerge. You may also notice their tail wagging as they interact with their siblings. Your puppy must start associating with people during this stage to prevent potential socialization issues later on.

2 Months Old American Bully

At two months of age, American Bully puppies undergo rapid growth. This period marks when they can receive their initial vaccinations from the veterinarian and settle into their permanent homes with their new owners. Your puppy is also developing important social skills, adjusting to new individuals, and becoming acquainted with their surroundings.

11-Week-Old American Bully

Your American Bully puppy will exhibit increased activity levels at eleven weeks old. However, it’s vital not to overexert them during this stage. Their growth plates and joints are still delicate and may not support sustained physical activity.

3-Months-Old American Bully

By the age of three months, your American Bully puppy enters the stage of youth. Their growth rate begins to slow down, and their senses should be fully developed. Regular socialization and training are crucial at this age, but patience is vital, as puppies have short attention spans.

4-Month-Old American Bully

Your American Bully puppy becomes a teenager at four months, exploring their boundaries and capabilities. This is an excellent time to start puppy training in order to instill good manners and prevent the development of undesired behaviors. Dedicate at least 20 minutes daily to training your dog during this stage.

6-Month-Old American Bully

Around the age of six months, your Bully puppy reaches sexual maturity. Female dogs may experience their first heat cycle during this period. While male dogs generally mature faster than females, it’s crucial not to consider breeding them at this age; they are still considered pups. YAt this period, you may notice behavioral changes such as increased irritation and rebelliousness. Additionally, your American Bully may become selective in choosing its companions as it ages. To avoid potential hostility against other dogs and strangers, comprehensive socialization and training are required.

1-Year-Old American Bully

By the time your American Bully reaches one year, they have matured to their full adult size and weight. It is time to move them from puppy food to adult food, and regular exercise is critical to preventing health problems such as obesity and diabetes. During this stage, your dog’s growth plates begin to harden and close, indicating their physical development is nearly complete. While their stature won’t alter much as they get older, their muscles will become more defined as they gain weight.

Diverse Personalities Among American Bully Puppies

American Bullies, known for their various proportions, are divided into four unique groups depending on their dimensions, demonstrating the breed’s versatility.

Standard American Bully

Male Standard American Bullies typically stand at 17 to 20 inches in height, while females range from 16 to 19 inches. Weight variations between males and females can range from 60 to 80 pounds. Their lifespan averages between 10 to 14 years. These Bullies often feature prominent, well-proportioned broadheads, defined cheek muscles, and robust skulls. Their physique exudes strength and muscularity, with well-defined mouths and imposing broad chests.

American Classic Bully

The Classic Bully possesses a more streamlined body and a noticeably leaner build while retaining their distinctive “bully” characteristics. They resemble the American Staffordshire Terrier or the original American Pit Bull Terrier. Classic Bullies maintain the same traits as Standard Bullies despite their more petite physique. In males, heights range from 17 to 20 inches, and in females, from 16 to 19 inches. Typical weights fall between 60 to 80 pounds, and their lifespan ranges from 10 to 12 years. Classic Bully physical features include commanding chests, slender bodies, and slightly less muscle mass. They boast broad shoulders and well-defined, slightly arched necks.

American XL Bully: The Giant of the Breed

The American XL Bully, while resembling the Standard Bully, stands out for its sheer size and stature. All American Bully types claim the title of the largest and heaviest due to their substantial body mass.

Male XL Bullies can reach an impressive weight range of 70 to 140 pounds and attain a towering height of 20 to 23 inches. While maintaining similar weight ranges, their female counterparts typically grow to heights ranging from 19 to 22 inches.

These gentle giants have large, powerful heads and broad, deep chests. Their distinguishing characteristics are well-formed cheek muscles and a highly defined jawline. They also have large shoulders and powerful, slightly arched necks, giving them a commanding presence among the breed.

American Pocket Bully: A Compact Powerhouse

American Pocket Bullies, though smaller in size, share many characteristics with their Standard Bully counterparts. They have muscular bodies, heads that are appropriate to their stature, and large chests.

Males normally stand 14 to 17 inches tall, while females are slightly shorter, being 13 to 16 inches tall on average. Their weight ranges from 20 to 50 pounds, and they normally live 10 to 12 years.

Despite their smaller appearance, Pocket Bullies exude strength and confidence, expressing the essence of the American Bully breed.

Promoting the Healthy Growth of Your American Bully

Ensuring the well-being and robust development of your American Bully involves several essential factors. Here’s a guide to help your Bully thrive with improved readability and SEO friendliness:


The American Bully’s muscle-centric physique demands a protein-rich diet, particularly as they mature. Puppies, in particular, benefit from foods rich in calcium for bone development and high-fat foods for energy. Provide your American Bully with nourishing meals three times daily to support their genetic potential and overall health.


Given their energetic nature and muscular build, American Bullies require regular exercise and activities to channel their abundant energy. Once your puppy has received the vaccinations, engage them in at least 30 minutes of daily exercise. Fetch and swimming are fantastic ways to teach obedience, trust, and a healthy energy release.


Begin obedience training as soon as your American Bully puppy arrives home. Training instils social skills and good behaviour in humans and other canines. Leveraging treats as rewards during training can be particularly effective, as Bullies thrive on positive reinforcement.

Vaccinations and Veterinary Care

Beyond providing a well-rounded diet, having a veterinarian’s guidance is crucial for your American Bully’s health. Veterinarians offer more than tick checks; they administer vaccinations and recommend booster doses. Vaccinations protect your Bully from potential illnesses and infections, especially during their early stages when their immune systems are still developing.

Vaccinations are often given between the ages of 6 and 14 weeks, and cover diseases like as rabies, distemper, and adenovirus. Vaccinations can also protect your Bully from risks such as COVID-19. Remember that vaccinations take some time to become effective, usually about a week or more. Regular booster shots may be required to maintain long-term immunity.

Veterinarians play a pivotal role in ensuring your Bully’s health and longevity. It’s essential to understand that regular vet visits are crucial even if your puppy appears healthy. And, having a pet insurance plan can ease the financial burden of these visits.

By addressing these aspects of care and wellness, you may ensure your American Bully’s long-term well-being and vigor.

The Significance of Veterinary Consultations for Your American Bully

We’ve stressed the significance of consulting with a veterinarian for the health of your American Bully in this article. Even if your puppy looks to be in good health, regular vet appointments are vital.

Veterinarians are critical in protecting the health and life of your Bully. Here’s why consulting with your vet is vital:

Comprehensive Health Assessment

Your veterinarian conducts thorough checkups to assess your American Bully’s overall health. This involves assessing your dog’s size, tracking weight, and spotting any problems before they arise.

Tailored Dietary Guidance

Vets provide expert dietary recommendations specific to your Bully’s needs. They can advise you on the best nutrition for your dog’s growth and well-being.

Preventative Care

Vaccinations, deworming, and other preventive procedures are critical for your Bully’s disease protection. Veterinarians administer vaccinations and offer guidance on when and how to protect your Bully from various health threats.

Timing of Neutering/Spaying

Your vet can advise you on the appropriate time for neutering or spaying your Bully, considering factors such as age and health. This decision is crucial for your dog’s long-term well-being.

Your veterinarian is your trusted partner in safeguarding your American Bully’s health. Their expertise and guidance should be valued and followed diligently to ensure your Bully enjoys a happy, healthy life.

Frequently Asked Questions (FAQs) about American Bully Growth

If you’re curious about how to promote healthy growth in your American Bully or have questions about their size and development, check out these frequently asked questions and their answers for improved readability and SEO-friendliness:

How Can I Promote Muscle Growth in My American Bully Puppy?

To help your American Bully puppy bulk up:

  1. Provide them with a nutritious diet rich in protein and calcium.
  2. Ensure an adequate fat intake as well.
  3. Consider seeing your veterinarian for nutritional supplements for specialized advice.
  4. Why Does My XL Bully Keep Growing?

The XL American Bully typically continues growing until around 24 months of age. It’s important to note that XL Bullies are naturally more significant than standard Bullies. If your Bully shows unusual growth beyond 24 months, it’s advisable to seek veterinary advice through regular checkups. Having pet insurance in place can provide additional peace of mind as you navigate your XL Bully’s extended growth period.

What Determines the Size of My American Bully Puppy?

The size of your American Bully puppy depends on several factors, including their specific breed class and their overall health and diet. American Bullies come in four sizes, ranging from 14 to 23 inches.

How Big Is a 10-Week-Old American Bully?

At ten weeks, an American Bully puppy is still small and has a long way to go before adulthood. However, this stage is ideal for socializing with both people and other dogs. The exact size can vary depending on the specific class of the dog.

These frequently asked questions about American Bully growth and development can help you better understand and care for your cherished pet.

Conclusion: Prioritizing Your American Bully’s Health and Growth

For first-time American Bully owners, the Bully growth chart serves as a valuable resource. It is essential to prioritize the well-being of your Bully to ensure they lead a happy and healthy life.

To provide your beloved American Bully with the quality of life they deserve, following the growth chart and taking proactive steps to care for their health is paramount. Collaborating with your veterinarian and breeder can help you establish a comprehensive growth and health plan.

By dedicating yourself to these measures, you not only gain peace of mind but also ensure a fulfilling life for your cherished Bully.

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