Crested Chickens, Vaulted Skulls, and Damaged Brains

These misshapen skulls hold equally misshapen brains. In 1998, scientists with the Vogt Institute of Brain Research at the University of Düsseldorf analyzed and compared the brains of white crested Polish chickens with brown leghorns and other noncrested breeds. They found that, “the brain has expanded to fill [the] larger endocranial space” created by “the protuberance of the head.” And, “as a consequence, the external morphology of the brain in [white crested Polish chickens] is drastically different from that in other breeds.”

 Some of the differences: The whole brain shows “pronounced elongation.” The telencephalon (the part of the brain responsible for fine control of movement, and interpreting touch, vision and hearing) is oddly shaped. It is described as “nearly round” compared to a structure that is “broader than long” in a brown leghorn. The meninges (the membranes that enclose the brain) and the telencephalon are so firmly fixed together “it was almost impossible to separate” them during the necropsy procedure.

In the brown leghorn, the cerebellum (a part of the brain that controls walking posture balance, coordination, and eye movements), the tectum (responsible for auditory and visual reflexes) and the telencephalon are all in close contact with each other. But in Polish chickens, these brain structures have all relocated, so that “there is no contact between them.” And the optic chiasm (the junction of the optic nerves from each eye; important in transmitting information from the eyes to the brain) has also relocated. It has moved backwards, and instead of pointing forward toward the beak, as it does in brown leghorns, it points in exactly the opposite direction.

 How does this bizarrely-shaped brain affect the behavior and intellectual capacity of the chicken? I’m not aware of any definitive conclusions in the scientific literature. But there are tons of anecdotes that span over a hundred years. In an 1868 book, Charles Darwin (yes, that Charles Darwin!) referred to some comments in an older source that described crested chickens as “extremely stupid.” He added his own observation of a crested chicken he owned that couldn’t find its way back to its feeding area when it was moved 100 yards away. Based on her research on learning behavior in chickens in the 1950’s – 1960’s, J. Schulze-Scholz, agreed with Darwin. Crested chickens, she reported, were apathetic, bad learners.

 But let us not be too hasty to clap a dunce cap on top of these birds’ crested heads. There’s also the research reported by Horst Requate in 1959. He studied white crested black Polish chickens for three years and didn’t find even a suggestion of stupidity. As a matter of fact, he found them to be “full of psychic energy” with no signs of disturbed behavior. He made only one modification to these birds for them achieve the same reaction to optic and acoustic stimuli as noncrested chickens. He cut away the crest feathers covering their ears and eyes.

The jury may be out regarding vaulted skulls causing altered behavior or reduced intelligence. But common sense suggests that the holes and open areas in vaulted skulls offer less brain protection. And there are a bazillion stories in chicken forums about crested chickens suffering neurological damage or sudden death. Often after an observed peck or blow to their head.

I’ve had three Polish hens in the ten years that I’ve been keeping chickens. I told Jennifer’s story in the opening paragraphs of Part 1 of this series. And there was Angie. Like Jennifer, Angie was in the group of chicks that made up my original flock. And like Jennifer, Angie was a white crested black Polish hen. She was the first chicken I ever lost. One winter morning I opened the coop door and saw Angie lying dead on the floor. There was a board on the floor next to her. I’d left a few loose boards in the coop about four feet off the floor. I think one of the other chickens had tried roosting on the board and knocked it loose. I think it struck Angie as it fell. It’s all conjecture based on evidence on hand when I found my dead hen. At the time, her fragility surprised me. A board fell a few feet and killed her. I didn’t know about vaulted skulls then. It makes a lot more sense now.

The following spring, when I put in my chick order, I included a golden laced Polish chick. I named her Angitou; “Angie Two.” Angitou grew into a beautiful chicken. She lived in a coop with the silkies and they were a big happy family. She was personable and loved for me to hold her. I found her dead on the coop floor when she was three years old. I have no explanation. A peck to the head? Maybe.

I’ve loved my Polish girls but I’ve not had good luck with this breed. When Jennifer passes on, I’ll be done with Polish chickens.

Jennifer’s brain damage is mild in the sense that she is still functional enough to eat and roost. Not every blow or peck to the head is fatal to vaulted-skull chickens. The severity of the brain damage that results from nonfatal injuries depends on the amount of brain swelling that occurs as a result of the injury. If the increased pressure causes their brain to swell through the holes in the skull, the chicken can suffer severe and probably fatal brain damage.

One result of brain swelling is the painful and often fatal condition called wry neck. The technical term is torticollis. Wry neck occurs with the cramping and contraction of the neck muscles. Flock-keepers find chickens suffering from wry neck with their head between their legs, twisted upside down, crooked sideways, or facing backwards. Wry neck is a symptom, not a disease. While the condition is a result of nerve damage, the cause of the nerve damage can range from Marek’s disease to vitamin deficiency to toxins. But if the chicken suffering wry neck is a crested bird, you should consider brain trauma.

In such cases, reducing brain swelling with an anti-inflammatory drug may save the hen. Gail Damerow in “The Chicken Health Handbook” suggests that aspirin may be helpful. She suggests 25 mg per pound, thus 125 mg for a five-pound bird. She also offers the caveat that prolonged exposure to aspirin can lead to kidney damage, and that you should never give asprin to a bleeding chicken (externally or internally), since it is an anticoagulant. A more focused, albeit expensive drug is the steroid prednisone, which requires a veterinary prescription.