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Freezing is a common welfare problem for backyard chickens that live in areas where temperatures are below freezing. It is a misconception among poultry farmers that 'hardy' breeds are invulnerable to freezing. All chickens are susceptible to frostbite, regardless of breed. The parts of the chicken's body most vulnerable to frostbite are their limbs: the comb, the comb, the toes, the feet and the legs. Roosters with single crests and large crests are at increased risk of frostbite in those parts of their bodies.
Chickens and other bird species experience something called a hunting reflex, which consists of intermittent vasodilation to help maintain the viability of the tissue in their limbs. However, as the temperature continues to drop, this vasodilation ceases. When tissue freezes and blood flow stops, extracellular ice crystals develop. This results in cell death and increased blood viscosity, which can lead to thrombosis. Vascular inflammation and thrombosis may not be limited to the injured extremity. Birds have an increased risk of secondary damage to their hearts.
Stages of freezing
The severity of frostbite can range from complete resolution without significant secondary complications, to gangrene, sloughing, and amputation of limbs after frostbite. Severity depends on factors such as absolute temperature, perceived temperature, duration of exposure, wet/dry cold, immersion, age and general health of the bird.
- First degree– Often called frostbite, where the surface of the skin freezes. The bird's comb or wattles turn an off-white, pale color. If their feet and legs are affected, they will look slightly red.
- Second degree– If freezing continues, the skin may completely freeze and harden, but the deep tissue is unaffected and remains normal.
- Third and fourth degrees- In severe frostbite, this phase affects all layers of the skin and the underlying tissues. As the affected tissue dries, it turns black (due to gangrene), slowly mummifies and falls away from the surrounding healthy tissue – at the so-called line of demarcation. The demarcation line in birds can take 3 to 6 weeks to develop.
When birds develop frostbite, the long-term effects seen in surviving tissue include increased susceptibility to cold damage, sensory loss, reduced circulation, and osteoarthritis.
Initial treatment
If the tissue is still frozen, slowly warm the affected parts of the body. Keep the bird in a comfortable living area where you won't risk exposing it to the cold again. Keep the affected body part clean and dry. Apply ointment and provide supportive care until you can get the bird to the vet.
It usually takes 10 days to 6 weeks for the tissue to present as necrotic and for the line of demarcation to form. The dividing line is the separation between healthy tissue and dying (necrotic) tissue. This process is extremely painful for the bird. They need to be taken to the vet.
What not to do
- Omissionuse direct heat (such as a heat lamp, hair dryer, heating pads, etc.) to rewarm the affected area.
- OmissionRub, massage, shake, or otherwise apply physical force to frozen tissue, as this may cause more damage to the affected area.
- Omissionallow chickens to walk on frozen feet or toes as walking will increase the injury. Limit movement by using a sling.
- Omissiontry to remove the black areas. These areas actually protect the remaining, living tissue. Removing the black areas can expose the underlying living tissue and increase the risk of secondary infections.
- Omissionput the chicken outside again.
- If there is a chance of an area refreezing,omissionTry to thaw, as thawing followed by refreezing can cause even more damage to the area.
Clinical symptoms
Pale discoloration to black discoloration of the points and edges of the comb and/or chips
Blisters of comb
Edema in the feet and/or legs
Blackening of feet and/or legs
Proprioceptive deficits (feet clenched, unable to straighten)
Mummified tissue
Diagnose
Reported cases
- Case 1: Frostbite in a parrotAn approximately 5-year-old female gray-headed parrot was evaluated after exposure to outdoor temperatures below -20°C (-4°F) for approximately 15 minutes. 22 hours. Severe frostbite of several fingers was noted, as well as dehydration and a depressed attitude. Treatment included oral antibiotics, antifungals, nonsteroidal anti-inflammatory drugs (NSAIDs), pentoxifylline, and topical aloe vera. Surgical amputation of the affected toes was not performed. Mild to moderate pododermatitis of the intertarsal joints developed due to a shift in weight bearing after the loss of most fingers. Within five months of initial presentation, all frozen toes were self-amputated and the bird was able to function independently without limitations in mobility.Ref
Therapy
| Name | Cv | |
|---|---|---|
| Supportive care | Bring the chicken inside and call your vet. Treatment should be started as soon as possible before necrosis occurs. | |
| Pentoxifyllin | 15 mg/kg PO q8-12 hours for 2 to 6 weeks; It has been shown to significantly improve tissue survival in frozen animals, both alone and in combination with aloe vera cream and aspirin. | J Wellehan 2003 |
| Surgery | Your vet may need to remove the necrotic tissue or perform amputation surgery in the late stages after the dividing line has formed. | |
| Antibiotics | To help prevent secondary infections. | |
| Painkiller | Freezing is extremely painful for birds and analgesia is essential. Tramadol, carprofen, meloxicam or gabapentin are indicated. No acetaminophen (Tylenol) or Ibuprofen. | |
| Apply aloe vera or SSD cream to the affected area. | ||
| Keep the area(s) as clean as possible | Bandages may be required for legs and feet and a daily soak in Epsom salt. |
Support
Prevention
- Protect your chickens from cold temperatures by winterizing the coop (insulate and prevent cold drafts), keep bedding dry, provide good ventilation to prevent moisture build-up, and provide a heat source (other than a heat lamp).
- After cold nights, perform a physical examination of each chicken, especially those with large tops and crests, for signs of frostbite.
Scientific references
- Tu, Huiyin, et al.Dexamethasone improves wound healing through reduced inflammation and increased vasculogenesis in the murine skin freezing modelWilderness and environmental medicine(2020)
- Laskowski-Jones, Linda & Jones, Lawrence J..Frostbite: Don't go outside in the coldNursing 2018(2018)
- .Rooster with frostbiteLittleton Animal Hospital(2015)
- S Honestly.FreezingUniversity of Maryland Medical Center(2014)
- C Handford et al.Frostbite: a practical approach to hospital managementExtreme physiological medicine(2014)
- D Swayne, J Glisson, L McDougald, L Nolan, D Suarez, V NairDisease in poultry.Wiley-Blackwell(2013)
- B ColesBasic Principles of Avian Medicine and Surgery: Third Edition.Blackwell Publishing(2007)
- J Wellehan, DVM, MSFrostbite in birds: pathophysiology and treatment.Compendium October 2003(2003)
- von Heimburg D, Noah EM, Sieckmann UP, Pallua N..Hyperbaric oxygen treatment for deep frostbite of both hands in a boy.Burns(2001)
- Calle PP, Montali RJ, Janssen DL, Stoskopf MK, Strandberg JD.Necrosis of distal limbs in captive birdsJ Wildl Dis.(1982)
- Valder JD, Flieg GM.Freezing and its consequences in exotic birds in captivity.J Am Vet Med Assoc.(1969)
- .Freezing at high altitudeJAMA(1944)
Good overviews
- J JacobFrostbite in chickens.Expansion(2015)
