Reviewing common emergencies of backyard poultry

By Olivia A. Petritz, DVM, DACZM

In the United States alone, there are an estimated 85 million backyard chickens, which represents a 28 percent increase from 2023 to 2025. According to a recent survey of backyard poultry owners, most people had kept chickens for only a relatively short period (less than five years). That same survey found minimizing predation was the most-cited challenge of poultry ownership.¹ Backyard chickens fall into a unique category of "pets," but they are also considered a major food-producing species in the United States, along with cattle, pigs, and turkeys. Therefore, government regulations, specifically for drug usage, supersede an owner's perception of their chicken's status.

A retrospective study reviewed emergency presentations for backyard chickens to a large hospital at an academic institution in the U.S.² Seventy-eight chickens presented on emergency during the three-year study period, and the average patient age was one year.

The most common emergency presentation was trauma from predation (32 percent), and the second was reproductive tract disease (13 percent). Forty-five percent of all hens presented on emergency were discharged, and 53 percent of them died. This article reviews the most common emergencies of backyard hens, including treatment options. It is important to note laws regarding drug administration in food animals, including chickens, vary from country to country, and the information presented here is specific to the United States.

Trauma

Predation trauma is the most common reason for emergency presentation of a chicken seen through the author's clinical service. Many wounds are deep, and the clinician should investigate all wounds for potential penetration into the coelomic cavity or the respiratory system (air sac), as these carry a much more guarded prognosis.

Radiographs are insensitive to evaluate for penetrating coelomic wounds due to the inability to distinguish free coelomic air from air contained within the air sacs, similar to other avian species. Lavage and cleaning of the wounds with any liquid should be performed with caution if the air sacs are thought to be involved. Bandaging and/or primary closure may be indicated, but the significant variability in wound types and locations precludes any overarching treatment recommendations (Figure 1).

Following any trauma, it is ideal to keep the chicken indoors until the wounds are healed to prevent myiasis and potential conspecific trauma. However, reintroduction of a chicken into an established flock can be challenging. Systemic antibiotics are indicated in cases of predation trauma, ideally based on culture and sensitivity of the wounds. However, antibiotic use is significantly more limited in this species than in other avian species due to regulatory concerns about meat and egg residues.

Like other major food-producing animals, certain drugs are prohibited in chickens, which include, but are not limited to, nitroimidazoles (metronidazole), chloramphenicol, and fluoroquinolone antibiotics. Clinicians who treat chickens, especially with any form of antibiotic, are encouraged to visit the Food Animal Residue Avoidance Databank (FARAD) website for additional details and updated regulations.

Analgesic therapy is also extremely important, but the clinician should be aware that many drugs are not approved for use in chickens and have unknown egg withdrawal times.

Meloxicam 1 mg/kg, administered orally twice daily, has been shown to reach effective plasma concentrations in white leghorn hens after single and multiple doses.^3,4 Egg withdrawal times were also reported in those manuscripts. Interestingly, these same researchers found there were significant breed differences in meloxicam pharmacokinetics after oral dosing between white leghorn chickens and Wyandotte and bantam Cochin hens, both of which are typically more common breeds seen in backyard flocks compared with commercial breeds.^5,6 The Wyandotte and bantam Cochin hens had overall a larger volume of distribution, slower metabolism, and slower clearance of meloxicam compared with white leghorn hens; therefore, the dose recommended in these breeds was reduced by half, at 1mg/kg orally once daily instead of twice daily. Unfortunately, at the time of publication, no information is available on pharmacokinetic data for meloxicam or other drugs in other chicken breeds.

Reproductive tract disease

Reproductive tract disease is one of the most common diseases of backyard chickens, as seen in the author's clinical service and reported in the literature.² Hens can present with a variety of clinical signs, many of which are nonspecific and often chronic/progressive—these signs include lethargy, hyporexia, and diarrhea.

Owners may also report reduced or absent egg production, which is often misinterpreted as egg binding (dystocia)—a disease process that is rare in chickens compared with other avian species.

Hens with a variety of reproductive tract diseases may also have varying degrees of coelomic fluid accumulation and distension, which is uncommonly recognized by owners prior to a physical exam (Figure 2). Ovarian neoplasia (adenocarcinoma) is very common in aged hens and can progress to carcinomatosis, leading to significant coelomic effusion in the end stages of this disease. Despite the large volume of coelomic fluid that can be present, affected chickens rarely present in respiratory distress. Conversely, this degree of coelomic effusion, regardless of the underlying etiology, often presents as dyspnea in parrots.

Salpingitis and oviductal impactions are also commonly diagnosed in older hens. If the oviduct is large enough, it is often palpable as a firm tubular structure (several centimeters in diameter) in the left dorsal coelom but may fill the entire coelom. Medical management for these impactions is often not successful due to the large amount of accumulated yolk and other material within the oviduct. Salpingohysterectomy will successfully remove the oviduct, although this procedure is challenging, even in large birds such as chickens. The ovary is rarely removed due to risks for fatal hemorrhage. Therefore, continued internal ovulation is a possibility in this species following oviductal removal.

The membranes surrounding the yolk are very delicate and can rupture, leading to free yolk in the coelomic cavity. Yolk induces a severe inflammatory response that results in peritonitis, with or without bacterial infection.  The signs of this disease are also usually nonspecific, and an enlarged, often fluid-filled coelom is a typical physical exam finding.

Coelomic organs are often challenging to interpret in survey radiographs of backyard poultry due to the lack of serosal detail and reduced air sac space in reproductively active hens. This is further exacerbated when coelomic effusion is present.

In contrast, coelomic ultrasounds often provide ample detail on coelomic organs, especially when fluid is present, and normal values have been published for hens.⁷ Coelomocentesis, with or without ultrasound guidance, is recommended for any chicken with palpable coelomic fluid. This can serve not only a diagnostic but also a therapeutic function. Repeated centeses are often necessary as the disease progresses, and this is also the case for other causes of coelomic effusion (ovarian neoplasia, etc.). The needle should be inserted ventrally on the coelomic midline to avoid the coelomic organs. Pocketing of coelomic fluid into the various normal coelomic cavities and concurrent peritonitis +/- adhesion formation can complicate coelomocentesis, even with ultrasound guidance.

Lameness

Three of the most common causes for lameness in backyard poultry include, but are not limited to, trauma, pododermatitis, and Marek's disease—the latter of which is more appropriately described as paresis. Causes of pododermatitis include trauma, inappropriate perch size/type, malnutrition, and anything that would cause an unequal weight bearing on their two pelvic limbs. Successful treatment first relies on correction of the underlying etiology.

A variety of antibiotics and analgesics have been utilized, and if severe, surgical debridement is often necessary due to the caseous nature of avian abscesses.

In addition, regional limb perfusion provides more localized antibiotic therapy for pododermatitis than oral antibiotics in this species.^8,9 Regardless of the treatment, this disease is often chronic and may require lifelong therapy (medical, surgical, or both).

Gallid alphaherpesvirus 2, also known as Marek's disease, is ubiquitous in all backyard chicken flocks, despite vaccination status. According to a mortality review of backyard chickens in the United States, neoplasia or lymphoproliferative diseases were the most common primary diagnosis (42 percent), and a majority of those cases were diagnosed as Marek's disease.¹⁰ There is varying strain virulence, and it is considered a highly contagious infection. The virus can survive for months in poultry litter or environmental dust. Infected chickens serve as carriers, and shedding can often be reduced by prior vaccination, but not completely prevented.

Four overlapping clinical syndromes of Marek's disease are described, but the most common (neurolyphomatosis) causes asymmetric paralysis of one or both pelvic limbs or wings due to mononuclear infiltrate within peripheral nerves. This may initially present as a unilateral lameness but will progress to complete paralysis of one or both pelvic limbs (Figure 3). Antemortem diagnosis is commonly made based on classical clinical signs, as PCR antemortem testing is often not sensitive nor specific to distinguish between naturally acquired infection vs vaccination.

Unfortunately, there is no effective treatment, and humane euthanasia is recommended. Vaccination for Marek's is administered on the 18^th day of incubation (in ovo) or immediately following hatching. Therefore, this is not typically done by veterinarians, but rather at breeding facilities. The vaccines are not 100 percent protective and require one to two weeks to produce effective immunity. Exposure of naïve chicks to the virus should be minimized during this time, but sadly, this is an uncommon practice.

Respiratory disease

Respiratory distress is an uncommon emergency presentation in backyard poultry compared with psittacines. Respiratory disease, however, is common in backyard poultry.

Differentials for respiratory disease in backyard flocks partially overlap with those of commercial poultry but are often distinct from common respiratory diseases of parrots. Mycoplasma gallisepticum is a common respiratory pathogen that can result in upper respiratory signs. Chronic mycoplasma infections can lead to sinusitis and infraorbital swelling (Figure 4). Many other infectious diseases can result in upper respiratory signs and infraorbital sinusitis, including, but not limited to, Avibacterium paragallinarum, Pasteurella multocida, and infectious laryngotracheitis (Gallid herpesvirus 1).¹¹

The tetracycline class of antibiotics are commonly used to treat mycoplasma in chickens; however, no antibiotic completely eliminates the organism. Mycoplasma gallisepticum is not a nationally notifiable disease in chickens, but it is a reportable disease in certain states, such as North Carolina.

Highly pathogenic avian influenza (HPAI) is relatively rare in backyard hens but is a significant regulatory concern because it is nationally notifiable. Since 2022, there has been an ongoing outbreak of HPAI H5N1 in wild and domestic birds.¹² Clinical signs develop rapidly in infected birds, and include respiratory changes, cyanotic and/or swollen combs and wattles, and neurologic abnormalities (tremors, torticollis, and opisthotonos). Acute mortality without clinical signs has also been reported. Death often occurs within 24 hours or less, and most highly pathogenic strains have a 90-100 percent mortality rate in poultry. If this disease is suspected in any poultry species, the state veterinarian's office should be notified immediately.

Olivia A. Petritz, DVM, DACZM, graduated from Purdue University and then completed several internships and a residency in the field of zoo and exotic animal medicine at the University of California, Davis. Dr. Petritz became a diplomate in the American College of Zoological Medicine in 2013, specializing in zoological companion animals (exotic pets). Petritz started an exotics service at a specialty hospital in Los Angeles, Calif., following her residency, and is currently an associate professor of Avian and Exotic Animal Medicine at North Carolina State University.

References

1. Elkhoraibi, C., et al. "Backyard chickens in the United States: A survey of flock owners." Poultry science11 (2014): 2920-2931.
2. Vaught, Meghan E., et al. "Reasons for evaluation on an emergency basis of and short-term outcomes for chickens from backyard flocks: 78 cases (2014–2017)." Journal of the American Veterinary Medical Association10 (2019): 1196-1203.
3. Souza, Marcy J., et al. "Pharmacokinetics and egg residues after oral administration of a single dose of meloxicam in domestic chickens (Gallus domesticus)." American Journal of Veterinary Research8 (2017): 965-968.
4. Souza, Marcy J., et al. "Pharmacokinetics and egg residues of meloxicam after multiple day oral dosing in domestic chickens." Journal of Avian Medicine and Surgery1 (2018): 8-12.
5. Souza, Marcy J., et al. "Breed differences in the pharmacokinetics of orally administered meloxicam in domestic chickens (Gallus domesticus)." Journal of the American Veterinary Medical Association1 (2021): 84-87.
6. Stilz, C. Robert, et al. "Pharmacokinetics and egg residues of oral meloxicam in Bantam Cochin chickens." Journal of Avian Medicine and Surgery2 (2022): 140-144.
7. Gros, Lucile, et al. "Ultrasonographic evaluation of the coelomic cavity in Rhode Island Red hybrid hens (Gallus gallus domesticus)." Veterinary Radiology & Ultrasound5 (2022): 620-632.
8. Clarke, Lorelei L., Cameron Ratliff, and Christoph Mans. "Clinicopathologic findings in chickens (Gallus gallus domesticus) administered amikacin through intravenous regional limb perfusion." Journal of avian medicine and surgery2 (2022): 187-191.
9. Ratliff, Cameron, et al. "Plasma and Tissue Amikacin Concentrations Following Regional Limb Perfusion of Chickens (Gallus gallus domesticus)." Journal of Avian Medicine and Surgery2 (2024): 91-97.
10. Mete, Aslı, et al. "Causes of mortality in backyard chickens in northern California: 2007–2011." Avian diseases2 (2013): 311-315.
11. Fulton, RM. Respiratory Diseases. In: Greenacre CB, Morishita TY, eds. Backyard Poultry Medicine and Surgery: A Guide for Veterinary Practitioners, 2^nd edition. John Wiley and Sons; 2021:218-228.
12. https://www.aphis.usda.gov/h5n1-hpai