✓Marek's Disease
HVT vaccination at hatch helps protect against the tumors, paralysis and other clinical effects of virulent Marek's disease. It does not necessarily prevent later field infection.
Hard Run Acres · Lakeland, Florida
Protection That Continues as They Grow
Our chickens aren't all the same age — and their vaccination needs aren't, either. At Hard Run Acres, we follow a structured, multi-stage chicken vaccination program instead of treating vaccination as only a day-one event.
Our vaccination journey
Begins at hatchPrimary series completed
With additional scheduled vaccinations as our chickens grow at the farm.
What the labels mean
Know Where Your Chicken Stands
We want you to know whether a bird is still moving through our vaccination program or has completed the primary series. The listing for each group is what matters when you shop.
Still progressing
Vaccination In Progress
These younger chickens have received the vaccinations scheduled for their current age, but they have not yet completed our full primary vaccination program. They still need additional scheduled vaccinations as they grow before reaching Fully Vaccinated status.
Primary series completed
Fully Vaccinated
Chickens that have completed the primary Hard Run Acres vaccination program, generally around 9–12 weeks of age. Additional optional boosters may be given to birds that remain at our farm longer.
Buying a younger chicken? If the bird stays at Hard Run Acres, we continue its scheduled program. If you take it home before completion, there is no requirement to continue the program. It simply hasn't received the later scheduled vaccines. If you'd prefer a bird that has completed our primary series, choose an older chicken marked Fully Vaccinated.
The program at a glance
What We Vaccinate Against
Our full chicken program addresses the following nine important disease categories. A younger bird will not yet have received every vaccination on this list. Vaccination reduces specific disease risks — it does not guarantee a bird will never become sick.
✓Coccidiosis
A live vaccine helps young chicks develop immunity through controlled cycling in their litter. Protection varies with management conditions. Watch for illness and act promptly even in vaccinated chicks.
✓Newcastle Disease
Vaccination aims to reduce serious illness associated with this contagious virus; vaccination is not a guarantee against infection or shedding.
✓Infectious Bronchitis
Respiratory vaccination addresses selected virus types. Because infectious bronchitis has many variants, not every strain is covered equally.
✓Gumboro (IBD)
Infectious bursal disease can damage a young chicken's developing immune system and reduce its ability to respond to infections and other vaccines. Breeding flocks may need additional pre-lay vaccination.
✓Mycoplasma (MG)
Our live F-strain vaccine helps control MG-related illness in chickens. F-strain-vaccinated birds remain carriers of the vaccine strain; read the important flock-mixing advice below.
✓Infectious Coryza
Vaccination targets important coryza serovars associated with facial swelling and respiratory disease. Protection depends in part on the circulating strains.
✓Fowlpox
Vaccination helps reduce disease caused by this virus, which can spread through contact and biting insects such as mosquitoes.
✓Avian Encephalomyelitis (AE)
AE vaccination is especially useful for future breeding hens: it helps prevent egg transmission and provides maternal antibodies that can protect their newly hatched chicks.
The exact vaccines and timing may differ with veterinary advice, vaccine availability and the bird group's documented history. See the independent veterinary references for the diseases and vaccination principles described here.
Real veterinary research · real backyard poultry
What Actually Makes Backyard Chickens Sick?
Marek's is serious. But Marek's is not the only serious threat — and a Marek's shot is not protection against all the other things that can make a chicken sick. Here's what researchers found when they examined birds that became ill or died.
Study 1: What was making small-flock birds sick or causing death?
Ontario, Canada · 245 birds examined, mostly chickens
21%Mixed respiratory infection was the primary diagnosis
11%Marek's disease was the primary diagnosis
Almost twice as many primary diagnoses involved mixed respiratory infections as Marek's. The infections often involved several organisms together, including MG, MS, infectious bronchitis virus and other bacteria or viruses.
The point: Marek's was not the leading diagnosis in this study. About 89% of these birds had a different primary diagnosis.
Brochu et al., 2019 · Read the study ↗
Study 2: Why isn't one vaccine enough to address every disease?
Eight U.S. states · 2,687 backyard birds examined
69%Had more than one disease or contributing diagnosis
42%Had bacterial disease findings
Parasitic disease was also reported in about 28% of the birds. The study found a broad mix of infectious and noninfectious problems. Marek's was important, too — but it was not the only diagnosis veterinarians encountered.
The point: Chicken illness often involves more than one problem. A vaccination against Marek's alone does not address MG, coryza, bronchitis, coccidiosis or other separate diseases.
Cadmus et al., 2019 · Read the U.S. study ↗
Why Hard Run Acres offers a broader program: Marek's vaccination is valuable, and we give it. But we don't stop there. As our chickens grow, our scheduled program also addresses other important infectious diseases rather than leaving Marek's as their only vaccination.
How to read these numbers: Both studies examined birds submitted for veterinary necropsy — not a random sample of healthy backyard flocks. They cannot tell us the lifetime odds that a typical Florida chicken will die from a particular disease. The Ontario numbers describe primary diagnoses; the U.S. percentages describe overlapping disease findings and must not be added together. Vaccination cannot prevent every cause of illness or death.
Why the hatchery experience looks different
Why Is Marek's the Vaccine You See Most Often at Hatcheries?
Because Marek's vaccination works best before early exposure, and hatcheries generally sell chicks right after they hatch. That is a timing issue — not evidence that Marek's is the only disease worth preventing.
1. Marek's is best vaccinated against at hatch
The Marek's virus is widespread and chicks can encounter it early. Vaccinating at hatch, before exposure, allows immunity time to develop. Hatcheries are ideally placed to provide that first dose.
2. Many other vaccinations happen later
Some other vaccines can also be administered at hatch, including coccidiosis vaccines. But many poultry vaccines need a later starting age or additional doses and boosters as the bird grows.
3. Day-old hatcheries don't keep growing birds
Most hatcheries send chicks to customers immediately, so they cannot complete vaccines scheduled weeks later. Hard Run Acres offers multiple ages, giving us the opportunity to continue a structured program during grow-out.
Bottom line: Marek's is commonly offered at hatch because that's when it should be given — not because it's the only important chicken disease.
Understanding Marek's without the myths
Marek's Disease: Four Facts Every Chicken Owner Should Know
Marek's deserves respect, not panic. Knowing how it spreads and what a diagnosis means will help you make better decisions.
It's widespread — even where no birds look sick
The virus is common in poultry environments. A flock can be exposed without every bird showing disease, and a property may be contaminated without its owner realizing it.
Contaminated dust can remain infectious for a long time
Infected birds shed the virus in feather dander that mixes with coop dust and litter. That contaminated material can remain infectious for months and, in some circumstances, years. That's an important reason to vaccinate chicks at hatch, before they encounter infected dust — not to wait until symptoms appear.
One Marek's case does not mean the entire flock will die
Not all infected birds develop clinical disease. Age, genetics, vaccine protection and viral strain affect outcomes. A diagnosed case deserves attention, but it does not predict that every chicken will become sick or die.
Not every sick or dead chicken has Marek's
Respiratory infections, parasites, reproductive disease, injuries and other illnesses also affect chickens. Even if one bird truly had Marek's, a second bird may die of something entirely different. Laboratory diagnosis is often needed to establish the cause.
Our approach: Vaccinate against Marek's at the appropriate early age, then continue addressing other infectious disease risks as our birds grow. Protection against one disease is useful; it is not a substitute for protection against others.
Veterinary references: Merck: Marek's Disease · Merck: Vaccination of Backyard Poultry · Penn State Extension: Marek's Disease
A major respiratory concern
Mycoplasma Gallisepticum (MG): Why It Matters
MG can contribute to chronic respiratory problems, including illness made worse by other bacteria or viruses. For backyard owners, the practical question isn't simply “Can I keep a perfectly MG-negative flock?” It's “How do I manage the risk of respiratory illness?”
MG can be difficult to spot
Some chickens show sneezing, nasal discharge, coughing or swollen sinuses. Others appear normal until stress or another infection makes symptoms more noticeable.
MG often contributes to mixed respiratory illness
MG can combine with infectious bronchitis virus, E. coli and other organisms, making respiratory disease more complicated than a single infection.
Treatment can relieve symptoms without eliminating MG
Appropriate antibiotics may reduce clinical signs, but they generally don't eradicate MG from an infected flock. That's one reason symptoms may return, especially when birds are stressed.
“MG-negative” is not an everyday backyard guarantee
Maintaining a verified MG-negative flock is a specialized, closely monitored process involving controlled sourcing, repeated testing and stringent biosecurity. Simply having healthy-looking chickens or routinely cleaning your coop does not establish an MG-negative flock. For typical open backyard flocks, we do not present that as an easy or dependable option.
What are the practical choices for a backyard owner?
1. Watch and manage
Some owners choose not to vaccinate against MG. They maintain ordinary flock care and respond if symptoms develop. This leaves birds without vaccine-derived MG protection.
2. Treat illness when needed
If respiratory disease develops, a veterinarian may recommend appropriate medication. Treatment can improve signs but may not clear an established MG infection or prevent recurrence.
3. Vaccinate to reduce illness risk
In appropriate flocks, MG vaccination is a preventive strategy to help reduce the severity and impact of disease. This is the approach Hard Run Acres has chosen under veterinary guidance.
Our philosophy: We focus on practical disease management for the backyard flocks we serve — not giving customers the impression that a small, open flock can readily maintain laboratory-confirmed MG-negative status. Published veterinary research explains why MG remains a persistent challenge even in commercial poultry and how medication and vaccination can help reduce losses.
One important distinction: Specialized MG-negative commercial breeding programs do exist, but they require much more than ordinary backyard precautions. They should not be confused with the routine keeping of ten or twenty backyard hens.
Hard Run Acres uses a live F-strain MG vaccine in chickens. This calls for special attention if you keep turkeys or maintain a formally MG-monitored breeding flock. Read our detailed F-strain and turkey precautions.
Veterinary references: Dr. Gary Butcher, UF/IFAS: Mycoplasma Gallisepticum — A Continuing Problem in Commercial Poultry · Merck: MG Infection in Poultry
Another important respiratory disease
Infectious Coryza: A Real Concern for Florida Flocks
Infectious Coryza is caused by the bacterium Avibacterium paragallinarum. It is a recognized problem in the southeastern United States, especially in flocks that keep or introduce chickens of different ages. It deserves attention alongside MG—not as a replacement for it.
Signs can resemble other respiratory diseases
Coryza may cause puffy or swollen faces, watery eyes, sneezing, thick nasal discharge, an unpleasant odor and reduced eating or egg production. MG, infectious bronchitis and other diseases can cause overlapping signs. You cannot reliably identify the cause just by looking.
New birds and long-term carriers matter
Infected chickens can pass Coryza through close contact, respiratory droplets or contaminated water. Some recovered birds remain carriers. This helps explain why the disease can return or spread in mixed-age flocks.
Stress and weather changes can play a part
A sharp change in conditions may stress birds and contribute to illness becoming noticeable in an already exposed flock. Weather doesn't create Coryza by itself: the disease requires infection with its causative bacterium. Other infections can make an outbreak worse or longer-lasting.
Why Hard Run Acres vaccinates
Because infectious Coryza is a recognized regional respiratory concern, we include a two-dose Coryza vaccine in our primary growing-bird program. It is designed to address important Coryza serovars and lower clinical disease risk, not to guarantee that no bird will ever become ill.
One practical lesson: Not every swollen face or nasal discharge is Coryza, and not every respiratory outbreak is MG. Both can be important, sometimes alongside other infections. Our vaccination program addresses both, but a confirmed diagnosis requires appropriate testing, such as Coryza PCR or bacterial culture.
Veterinary references: Merck Veterinary Manual: Infectious Coryza · UF/IFAS: Common Poultry Diseases
Important for every new chicken owner
Coccidiosis Vaccination: A Better Start, Not a Guarantee
Our chicks receive a live coccidiosis vaccine at hatch. But this vaccine doesn't work like flipping a switch. Chicks must develop immunity through controlled exposure as the vaccine organisms cycle in their litter. Conditions and individual responses vary, so one flock may develop more consistent protection than another.
The vaccine needs time to work
After vaccination, the mild vaccine organisms multiply and are passed in droppings. Re-exposure helps the chick build immunity. Some species in Coccivac-D2 need additional cycles, so litter and management conditions matter through the early growing period.
Too dry or too wet can cause problems
Very dry litter can interfere with vaccine cycling. Wet, heavily contaminated areas can encourage excessive cycling and disease pressure. Clean water, suitable litter conditions and avoiding overcrowding remain important.
Learn the warning signs
Watch for chicks becoming unusually quiet, fluffed up or hunched, eating and drinking less, losing weight, passing loose or bloody droppings, or suddenly becoming weak. Not every coccidiosis case produces visible blood. Several sick chicks or unexpected deaths deserve immediate attention.
Act on illness—even if chicks were vaccinated
If signs suggest coccidiosis, don't assume the vaccine has everything covered. Check the birds promptly, correct wet litter or water problems and arrange appropriate treatment rather than waiting for more chicks to get sick. Amprolium is one commonly used treatment option for clinical poultry outbreaks.
Important: Never ignore a suspected coccidiosis outbreak because the chicks were vaccinated.
Vaccination is prevention, not emergency treatment. If chicks become lethargic, stop eating, develop diarrhea or bloody droppings, or mortality rises, take action promptly. A veterinarian or poultry diagnostic service can help if the cause is uncertain, symptoms are severe or treatment isn't helping. Several other illnesses can mimic coccidiosis.
Amprolium and other anticoccidial treatments can interrupt live-vaccine cycling, which is one reason they generally aren't used routinely during initial vaccine development. But treating a genuinely sick flock takes priority over preserving the vaccine's cycling process. Use a poultry-appropriate product according to its label and applicable food-animal guidance; never delay necessary care just because the flock was vaccinated.
Sources: Merck Veterinary Manual: Coccidiosis · Merck Animal Health: Coccivac Management Guide · Coccivac-D2 label and product information
The rest of the vaccination program
Other Important Protection as Chickens Grow
These five diseases are also part of the Hard Run Acres chicken vaccination program. Some matter especially for respiratory health, some for Florida's mosquitoes, and others for birds you may eventually use for breeding.
✓Infectious Bronchitis (IB)
This extremely contagious virus can cause coughing and sneezing and can affect egg production and quality. Different strains matter. Our program includes Massachusetts and Connecticut vaccine types; these do not guarantee protection from every possible field variant.
✓Newcastle Disease (ND)
Newcastle viruses can cause respiratory disease and, with virulent forms, severe illness. Our program includes B1 and LaSota Newcastle vaccine strains as part of its scheduled vaccination and booster approach. LaSota is a Newcastle strain, not an infectious bronchitis strain. Routine vaccination doesn't mean we are claiming that virulent Newcastle is a common local outbreak.
✓Fowlpox
Mosquitoes and other biting insects can carry fowlpox between chickens. Dry fowlpox produces skin lesions or scabs; the wet form can affect the mouth and upper airway and be much more serious. Vaccination is valuable in areas with mosquito exposure.
✓Infectious Bursal Disease (IBD / Gumboro)
IBD can damage the bursa, a key organ in a young chicken's developing immune system. Early damage can reduce its ability to fight other infections and respond to vaccines. IBD matters for future breeding birds too: a dedicated pre-lay breeder program may be needed to provide strong maternal antibodies to their chicks.
✓Avian Encephalomyelitis (AE)
AE can cause tremors and other neurologic problems in chicks. It has a particularly important breeder connection: vaccination before hens begin laying helps prevent transmission through eggs and provides maternal antibodies that protect newly hatched chicks.
Planning to raise breeding chickens? Choosing a bird that has completed our primary vaccination program can be a valuable head start compared with a bird that has only received a hatch-day vaccine. However, Fully Vaccinated does not mean a bird has completed every vaccination that a future breeding flock may need. Some breeder programs use additional pre-lay IBD and other vaccines depending on their goals and veterinary guidance.
Veterinary references: UF/IFAS: Infectious Bronchitis Virus · Merck: Poultry Vaccination Programs · Merck: Fowlpox · Merck: Infectious Bursal Disease · Merck: Avian Encephalomyelitis
Why a multi-stage program?
More Than a Single Hatch-Day Vaccine
Start early
Early vaccination is particularly valuable for diseases such as Marek's. Our program begins at hatch and continues as birds grow.
Continue through growth
Different vaccines are scheduled for appropriate stages; certain vaccines require additional doses. We track progress for each bird group.
Explain what was completed
Customers can see whether the primary series is still in progress or complete and ask about the group's vaccination history.
Why we believe this matters
Backyard flocks can face exposure from newly introduced birds, contact with other poultry, insects, contaminated equipment and their environment. Vaccination is one risk-management tool alongside good nutrition, sanitation, biosecurity and flock management.
How our program was developed: We consulted Dr. Gary Butcher, a University of Florida poultry veterinarian, while developing our vaccination program for backyard chickens. We explained our goals and the practical challenges, and he recommended which vaccines to use and when to administer them. Those recommendations helped shape the program we follow at Hard Run Acres.
Read Dr. Butcher's UF/IFAS publication ↗Hard Run Acres operates its vaccination program independently. Our consultation and these scientific references do not imply an official endorsement or certification by the University of Florida.
Customer questions
Frequently Asked Questions
Each question starts with a direct answer. Tap or click any question for the fuller explanation and supporting veterinary research.
If one chicken develops Marek's, will all the others die?No. Infection and serious illness are not the same, and a diagnosis in one bird doesn't predict the outcome of the entire flock.
Marek's is widespread, but clinical disease varies with age, viral strain, genetics and immunity. Other sick or deceased chickens may have different problems. A veterinary laboratory can help confirm a cause when an accurate diagnosis is important.
Merck — Marek's Disease ↗Why don't most hatcheries complete all those other vaccinations?They usually sell chicks on hatch day. Other vaccines and boosters are scheduled after those chicks have left the hatchery.
Hatch-day Marek's vaccination is valuable, but it is not proof that other diseases are unimportant. Some vaccines, including coccidiosis and certain respiratory vaccines, can also be given at hatch; other programs require later timing and boosters. Because Hard Run Acres raises birds through multiple ages, we have opportunities to administer later doses.
Merck — Poultry Vaccination Programs ↗If my flock has always been healthy, why vaccinate?Vaccination is preventive: it is intended to help before a disease exposure occurs.
Never having seen a disease is not proof it cannot be introduced by new birds, equipment, visitors or the environment. Whether to use an individual vaccine depends on the species, disease risk, flock type and veterinary guidance. At our farm, we've chosen a structured preventive program because we raise and sell birds of multiple ages.
Source: Butcher & Miles, UF/IFAS — Vaccine Failure in Poultry: Factors to Consider ↗Can a vaccinated chicken still get sick?Yes. Vaccines reduce particular risks; they don't make birds immune to every disease.
Protection varies with the vaccine, the bird's immune response, vaccine administration, disease strain and level of exposure. In addition, a chicken may have illnesses that are not included in its vaccination program. Good hygiene, quarantine, nutrition and veterinary care remain essential.
Source: UF/IFAS — Vaccination Failure in Poultry ↗What does “Fully Vaccinated” mean at Hard Run Acres?The bird completed our primary chicken vaccination series, usually around 9–12 weeks.
This is a description of our primary program, not a promise of lifelong immunity. If a bird remains at Hard Run Acres, we may also administer a later optional Newcastle/infectious bronchitis booster around week 16. That optional booster is not required for the Fully Vaccinated designation. Ask us about the actual dates and vaccines for the group you're considering.
What if I buy a chick while vaccination is still in progress?Additional vaccinations remain. Ask us for the group's history before you bring it home.
Vaccination In Progress means the chick has received the vaccinations scheduled for the stages it has reached at our farm, but has not completed our primary series. That's normal for a younger chick. Many backyard chickens are purchased with no vaccinations, or with only a hatch-day Marek's vaccination. You do not have to arrange additional vaccinations to buy or raise one of our younger birds. It still needs normal care and sensible biosecurity, and it will not have the additional disease protection offered by doses it hasn't received. If you prefer a chicken that has completed our program, choose one of our older birds listed as Fully Vaccinated.
Can I simply add your vaccinated chickens to my current flock?Not without planning. Vaccination doesn't replace quarantine and flock compatibility checks.
Quarantine, housing arrangements, health history and the vaccine strains used all matter. In particular, birds vaccinated with live F-strain MG deserve special consideration before being introduced into existing flocks. Customers maintaining MG-negative or monitored breeding flocks should discuss compatibility with their veterinarian before purchase. We also recommend careful gradual introduction for ordinary backyard flocks.
Source: Merck Veterinary Manual — Mycoplasma gallisepticum ↗Can a vaccine itself cause a reaction?Some vaccines can cause temporary reactions, and no vaccination program is free of tradeoffs.
Live poultry vaccines stimulate an immune response and may cause mild vaccine reactions. Improper timing, application, bird health and the particular organism can affect results. That is one reason vaccination needs to be thoughtfully scheduled rather than advertised as a miracle cure.
Source: UF/IFAS — Vaccine Failure in Poultry: Factors to Consider ↗Can I feed a coccidiosis-vaccinated chick medicated starter?Check before using amprolium-medicated feed; it can interfere with live coccidiosis vaccine cycling.
Live coccidiosis vaccines rely on controlled replication of vaccine organisms to develop immunity. Amprolium and some other anticoccidials can suppress that process, especially during early vaccine cycling. We generally favor nonmedicated starter during the initial vaccine-establishment period unless the product instructions or a veterinarian recommend otherwise. If a vaccinated chick develops signs of coccidiosis, however, don't delay appropriate treatment to protect vaccine cycling. Amprolium is commonly used for clinical outbreaks, with care taken to follow poultry labeling and obtain diagnostic advice if the illness is uncertain or severe.
Merck — Coccidiosis ↗Does your program use mRNA vaccines?No. Our current chicken vaccination program does not use mRNA vaccine technology.
We use established veterinary vaccines selected for the particular diseases in our program, including live vaccines and other conventional poultry products. Vaccine technologies differ from product to product. We are happy to discuss which product was administered to a particular group.
Myths, misconceptions & important distinctions
What the Science Actually Says
Vaccines deserve thoughtful questions and truthful answers. Here are a few common claims, with the essential facts up front and sources behind them.
“The Marek's vaccine brings Marek's disease onto my property.”Our HVT vaccine does not contain the virulent chicken Marek's disease virus that causes tumors and paralysis.
The HVT vaccine is a live turkey herpesvirus (Meleagrid alphaherpesvirus 1), a distinct, naturally avirulent virus used to stimulate protection against virulent Marek's disease. It is not correct to describe HVT vaccination as deliberately introducing the virulent chicken Marek's disease virus. Importantly, it is still a live vaccine, and HVT vaccination does not necessarily prevent a chicken from acquiring or shedding a virulent field strain later.
Source: Merck Veterinary Manual — Marek's Disease ↗Source: Merck — Vaccination of Backyard Poultry ↗“If a vaccinated bird can still carry disease, the vaccine doesn't work.”Not true. Preventing severe illness and preventing all infection are different outcomes.
Some poultry vaccines primarily reduce clinical disease or its severity rather than producing sterilizing immunity. Marek's and Newcastle vaccines are important examples. This does not make vaccination useless; it means customers should understand exactly what type of protection the vaccine is expected to provide.
Source: Merck — Newcastle Disease ↗“One Marek's shot is all the vaccination a backyard chicken needs.”Marek's vaccination is valuable, but it doesn't protect against unrelated poultry diseases.
Marek's vaccine addresses Marek's disease. It does not protect against coccidiosis, Newcastle, coryza or other diseases. Which additional vaccines make sense depends on the animal's age, location, management and exposure risks. Our program was designed to address several separate disease categories rather than relying on a single hatch-day vaccine.
Source: Merck — Vaccination Programs for Poultry ↗
Important flock compatibility information
MG F-Strain and Turkeys: Putting the Risk in Perspective
A real precaution — not a blanket claim that nobody with turkeys can own vaccinated chickens
Here's what customers need to know: Our live F-strain Mycoplasma gallisepticum vaccine is intended for chickens. Vaccinated chickens remain carriers of the vaccine strain, which can spread through close contact. Veterinary references describe F-strain as relatively low-virulence in chickens but capable of causing disease in turkeys.
Housing and biosecurity matter. Chickens and turkeys living in the same pen or sharing close contact present an avoidable exposure concern. Separating flocks in different facilities, limiting shared equipment and managing people and airflow can reduce opportunities for spread; simply owning both species on the same property does not establish that transmission will occur. There is, however, no scientifically justified minimum separation distance that guarantees safety for every farm.
What does research show? A 2012 Poultry Science experiment inoculated turkeys with F-strain MG and used adjacent and downstream poultry pens. It did not detect MG infection in birds housed in the separated down-airflow pens during the trial. This supports the point that transmission across separation is not inevitable, but it does not prove that a particular distance is always safe or directly test vaccinated chickens infecting turkeys. A separate 2019 study demonstrated F-strain transmission between chickens in close contact.
Our recommendation: If you keep turkeys, or maintain an MG-negative or monitored breeding flock, tell us before purchasing so you can review your setup and speak with a poultry veterinarian. The goal is informed flock management, not false reassurance or needless alarm.
Merck Veterinary Manual — MG risks and vaccine strains ↗ Purswell et al., 2012 — Transmission and housing separation ↗ Elliott et al., 2019 — F-strain transmission between chickens ↗
Independent evidence
Veterinary Research & References
We believe customers should be able to check the science for themselves. These resources are from veterinary manuals, university Extension publications and peer-reviewed research. They support specific facts and principles; they are not endorsements of Hard Run Acres.
- Gary D. Butcher & Richard D. Miles, UF/IFAS — Vaccine Failure in Poultry: Factors to Consider
- Gary D. Butcher & Fred Rossi, UF/IFAS — Prevention and Control of Fowl Pox in Backyard Chicken Flocks
- Merck Veterinary Manual — Vaccination of Backyard Poultry
- Merck Veterinary Manual — Marek's Disease in Poultry
- Merck Veterinary Manual — MG Infection in Poultry
- Merck Veterinary Manual — Infectious Coryza
- Merck Veterinary Manual — Coccidiosis in Poultry
- Merck Veterinary Manual — Vaccination Programs for Poultry
- Merck Veterinary Manual — Infectious Coryza, diagnosis and prevention
- UF/IFAS — Common Poultry Diseases, including Coryza
- Merck Animal Health — Coccivac Management Guide
- Merck Veterinary Manual — Infectious Bursal Disease
- Merck Veterinary Manual — Avian Encephalomyelitis
- Brochu et al., 2019 — Ontario small-flock causes of illness and death
- Cadmus et al., 2019 — Mortality in backyard poultry in eight U.S. states
- Penn State Extension — Marek's disease in chickens
- Purswell et al., 2012, Poultry Science — MG F-strain and transmission under separated housing
- Elliott et al., 2019, Poultry Science — MG F-strain transmission between chickens
Educational information only. Vaccination decisions, quarantine plans and treatment for an ill bird should be made with attention to the individual flock and guidance from a qualified poultry veterinarian.
Find your next flock additions
More Breeds. More Ages. More Protection.
Explore available chickens at Hard Run Acres. If you have questions about a particular bird group's vaccination status, we're happy to help you understand it before purchase.