In extremely cold weather, backyard chickens are at risk for frostbite; the possible consequences of frostbite are pain, disfigurement, loss of mobility, decreased fertility and diminished egg production in hens. Mild cases are often unavoidable even with the best preventative efforts of diligent chicken-keepers, but knowing the causes, how to optimize a flock’s living conditions and how to treat frostbite if it occurs will reduce the risks while limiting pain and damage.

My snowy chicken coops.

WHAT IS FROSTBITE?
Frostbite is damage that occurs to bodily tissues from exposure to extreme cold when fluid in cells freezes. As a result of freezing, blood clots form, depriving the cells of oxygen, causing tissue damage to varying degrees. In extremely cold conditions exposed tissues can suffer frostbite in minutes.
National Weather Service Wind Chill Temperature (WCT) index:

  • Calculates wind speed at an average height of 5 feet, the typical height of an adult human face, based on readings from the national standard height of 33 feet, typical height of an anemometer
  • Is based on a human face model (emphasis added)
  • Incorporates heat transfer theory based on heat loss from the body to its surroundings, during cold and breezy/windy days
  • Lowers the calm wind threshold to 3 mph
  • Uses a consistent standard for skin tissue resistance
  • Assumes no impact from the sun, i.e., clear night sky.”

Factors that can contribute to frostbite are:

  • temperature
  • wind chill factor
  • exposure duration
  • humidity/moisture
  • high altitude
  • diminished circulation
This is a normal, healthy comb and healthy wattles.

CHICKENS AT RISK
In cold weather, chickens are able to conserve body heat by restricting blood-flow to their combs, wattles and feet, the very parts of the body that give off excess heat in warm weather. The result is a decrease in warmth and oxygen to those extremities, which puts them at risk for frostbite.

Blackened area on tip of comb indicates frostbite.

Water dripping onto wattles puts the chicken at risk for frostbite in very cold temps. Chickens with large combs and wattles are especially vulnerable to frostbite, but any chicken can be affected if the conditions are cold enough. Wattles are especially susceptible to frostbite since drinking water often drips from the beak, down the wattles.

Roosters and breeds with single combs are at the greatest risk of frostbite due to their more prominent projection. Frostbite to feet is an equal-opportunity affliction.

Normal chicken feet.

Frostbite on toes.

This is a mild case of frostbite to the comb and wattles that occurred when temperatures were in the teens one day and the wind chill brought the temps to below zero. The roosters insist on patrolling the perimeter of the coops, which puts them at high risk for frostbite with their large combs and wattles. Chickens should be kept in a fully covered, winterized chicken run in super cold temperatures.

Slight color change in the wattles indicates mild frostbite.