What Causes Black Spots on a Chicken’s Comb?

Black spots on a white chicken

Chicken enthusiasts may find themselves startled by the sight of black spots on a chicken’s comb. While it can certainly be a cause for concern, there are various reasons why a chicken may develop these black spots. In this article, we will explore the different causes and potential treatments for black spots on a chicken’s comb. So, let’s dive in!

Congealed Blood: A Common Culprit

Black spots on a chicken’s comb are often the result of congealed blood. The comb, being an active organ responsible for regulating body temperature, contains numerous blood vessels and small capillaries. This vascular nature makes it prone to minor injuries and subsequent bleeding. Even small injuries can lead to the formation of black spots, ranging from small nodules to thick, dark scabs.

Black spots resulting from peckmarks on a chicken's comb

These injuries can occur both externally, through accidents or peck marks, and internally, as a result of diseases. However, it’s important to note that most diseases affecting the comb will lead to a change in its overall color, rather than the development of black spots. Lack of oxygen, for example, can darken the comb, turning it bluish or purple. In this article, we will focus specifically on black spots on a chicken’s comb.

Let’s Explore the Causes

Peck Marks

Many times, black spots on a chicken’s comb are simply peck marks. Chickens peck each other as a way to establish and maintain their pecking order. Roosters, in particular, may engage in battles where they peck at each other’s comb.

Black spots resulting from peck marks on a campine chicken

If the peck marks are severe wounds, they can be treated similarly to fowlpox. In some cases, pecking can become excessive, turning into bullying. This often happens when larger birds are placed with smaller ones or when there is limited space. To address this, temporarily isolating the bully or using pinless peepers can help reduce tension. If you’re unsure about the space requirements for your flock, you can use our chicken coop size calculator.

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Fowlpox is a contagious viral disease that can cause black nodules and scabs to form on a chicken’s skin. It primarily affects the unfeathered areas, including the comb, eyes, wattles, and legs. The black spots associated with fowlpox develop gradually, starting as small pimples that evolve into white or yellowish nodules before transforming into thick, dark scabs. In severe cases, fowlpox can even lead to blindness if it spreads over the eyes.

Nodules and scabs caused by fowlpox

Unfortunately, there is currently no cure for fowlpox, and the best course of action is to allow the disease to run its course while providing supportive care. It’s crucial to clean and disinfect the scabs to prevent secondary infections. Additionally, boosting the chicken’s immune response with extra vitamin A can help alleviate the symptoms.


The comb and wattles of a chicken are sensitive to freezing temperatures. Frostbite can occur within minutes to hours of exposure to freezing temperatures, especially when accompanied by strong winds. The fluids inside the comb freeze, forming ice crystals and leading to blood clots. As a result, the tissue in the comb turns pale, then grey, and ultimately black.

Frostbite on a chicken's comb

Chickens with larger combs are more susceptible to frostbite, as their bodies try to retain warmth by reducing blood flow to the comb. However, even cold-hardy breeds with smaller combs can experience frostbite. Typically, frostbite starts at the tips of the comb in freezing temperatures. For more severe cases, applying a healing ointment can help protect and support the comb.

Flea Infestation

Fleabites can result in tiny black spots on a chicken’s comb and wattles. The sticktight flea (Echidnophaga gallinacea) is a common ectoparasite that infests not only chickens but also dogs, cats, and birds. These female fleas attach their heads to the chicken’s skin to feed on their blood.

A chicken with flea infestation

Fleas remain attached to the chicken’s skin, even when laying eggs. The eggs are then dropped in the chicken’s roosting areas, where they develop into larvae. After about two weeks, they become adult fleas and seek another chicken to attack. Fleas prefer unfeathered areas, such as the comb, wattles, and around the eyes. Their bites can be painful and may lead to secondary skin infections, weight loss, anemia, and even death. Carefully removing the fleas with tweezers and applying antibiotic ointment can help resolve the issue. Additionally, thorough cleaning of the chicken coop and removal of bedding are essential to tackle an infestation.

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Red Mites

Red mites are blood-sucking ectoparasites that can quickly turn into a plague for wild birds and chickens. Unlike fleas, red mites do not attach themselves to the chicken’s skin. During the day, they hide in cracks and crevices within the chicken coop, only emerging at night to feed on the chickens for around an hour. Their bites can lead to skin irritation, rashes, scarring, and the development of black spots on the chicken’s comb.

Red mites infesting a chicken's comb

Red mite infestations can cause stress, feather pecking, aggressive behavior, and sleep deprivation in chickens. To combat a red mite infestation without using pesticides, methods such as using a blow torch, garlic, disinfectant, and sealing cracks and crevices with paraffin can be effective.


Mosquito bites can result in bite marks and, consequently, black spots on a chicken’s comb. Mosquitos can also transmit diseases like fowlpox and chicken malaria. While some mosquito species may naturally dislike the odor of chickens, it does not prevent them from biting.

Mosquitos near a chicken coop

While it may be challenging to completely eliminate mosquitos, several measures can be taken to reduce their presence. These include avoiding stagnant water, using mosquito traps, installing mosquito mesh netting, using insecticidal spray, and planting mosquito-repelling herbs like citronella and lavender. However, it’s important to avoid using chemical diffusers or repellents that contain toxic pesticides harmful to chickens. Stagnant water or slow-moving rivers can also lead to algae poisoning in chickens, causing death within a short amount of time if the contaminated water is ingested.

Other Flying Blood-Sucking Parasites

Various flying parasites feed on the blood of chickens, leaving bite marks that can result in black spots on a chicken’s comb. Examples include the biting midge, which can transmit skin mites, and the black fly, which thrives in tropical climates and attacks chickens in swarms, potentially transmitting diseases.

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Other Potential Causes

In addition to the specific causes mentioned above, there are instances where black spots on a chicken’s comb can arise from other factors. One such example is favus, also known as avian ringworm. Favus is a fungal skin infection that begins as white spots on the comb. As the infection progresses, a wrinkled crust may develop. These white areas can coexist with black spots resulting from physical damage or pecking. Favus can be particularly severe when it spreads to feathered areas, leading to feather loss. It is more common in chickens living in humid and damp regions.

On the other hand, sometimes the apparent black spots on a chicken’s comb may simply be dirt. Chickens do not bathe in water like humans but instead use dust to cleanse themselves. Occasionally, dirt or mud may become stuck on the comb, creating the illusion of black spots. Before jumping to conclusions about diseases or parasites, it’s worth attempting to clean the comb to see if the spots can be easily removed.


In summary, black spots on a chicken’s comb can have various causes. They may be the result of peck marks, fowlpox, frostbite, flea infestations, red mites, mosquito bites, or other flying blood-sucking parasites. Furthermore, favus or simple dirt can also lead to the appearance of black spots. Understanding the potential causes and treatments for black spots on a chicken’s comb is essential for maintaining their health and well-being.

If you’d like to learn more about chicken health problems, symptoms, and diseases, be sure to visit our Health Page. You’ll find a helpful Symptom Checker, an extensive list of Chicken Behavior articles, and valuable insights into the most common Chicken Diseases. Alternatively, you can explore our comprehensive articles in The Classroom section.