Hypothermia, or low body temperature, is a condition that occurs when a chicken's core body temperature drops below 107°F (41°C). It is caused by prolonged exposure to cold, wet or windy conditions.
Hypothermia is considered an emergency and requires immediate treatment. Left untreated, it can lead to cardiac arrest and death.
Clinical signs of hypothermia in chickens vary depending on the severity of the condition. Hypothermia is classified into three stages which include mild, moderate and severe.
Mild hypothermia
Chickens with mild hypothermia will have a body temperature between 140 to 96.8°F (40 to 36°C). Signs of mild hypothermia include:
- Huddling with other birds.
- Increased heart rate.
- Rapid breathing.
- Pale face and comb.
Moderate hypothermia
Chickens with moderate hypothermia will have a body temperature between 95 to 84.2°F (35 to 29°C). Signs of moderate hypothermia include:
- Reduced heart rate.
- Cyanosis - bluish face and/or comb.
- Dilated pupils.
- Abnormal heart rhythm.
- Increased muscle stiffness.
- Recumbency.
- Decreased shivering.
- Weakened reflexes.
Severe hypothermia
Chickens with severe hypothermia will have a body temperature below 82.4°F (28°C). It is important to keep in mind that chickens with severe hypothermia will appear dead and are unfortunately, commonly mistaken for dead. These birds can still be saved with appropriate treatment. Signs of severe hypothermia include:
- Recumbency, loss of consciousness.
- Rigid body.
- Body is cold to touch.
- Loss of voluntary motion
- Heart stops beating.
- Coma, that may appear dead.
- Death
Chickens are at high risk of developing hypothermia during the colder months of the year. Hypothermia is the most common cause of death of chickens during the winter. This is largely due to the abundance of misinformation that is circulated amongst backyard chicken keepers about winterizing methods and physiology of chickens.
Treatment
Treatment of chickens with hypothermia requires rewarming and is like what is done in humans and other animals. Rewarming may be passive, active external, or active internal.
The bird should be moved into a clean, dry, and warm environment under 30°C (86°F). Any visible water or snow should be removed by gently patting with a warm towel.
Birds who are conscious with mild hypothermia can be rewarmed passively by simply keeping them in the warm environment.
Birds with a core body temperature of 95°F (35°C) and below, who are most likely unconscious or barely conscious will require the use of active external warming technique.
The active external warming technique consists of active and gradual rewarming, over a period of hours until their core body temperature rises to at least 40°C (104°F).
Reheating equipment should ideally be heated to a temperature of 45–48°C (113–118.4°F) and can consist of a brooder heat plate, radiant heater (including coop heaters), heating pads, warm blanket, or water. Do not use chemical heat pads. A brooder heat plate is ideal.
While rewarming the bird, make sure to concentrate (or expose) the chest and under wing areas first, as these are areas with major blood flow which will circulate to the core organs. Hold for 1-2 minutes, followed by the sides and later the extremities for the same period, then a break of 2 min.
Repeat numerous times over a course of hours until the bird’s body temperature rises to at least 40°C (104°F). Positive signs include stretching legs and wings, blinking eyes, opening beak, conscious, responsive, standing. Don’t offer food while rewarming.