The Life and Times of Betty the Transgender Chicken - Spontaneous Sex Reversal in Chickens

It was a melancholy day in June when I went to the coop to commiserate with the flock. I had just buried Arlene, my favorite Barred Rock hen and I was in need of some solace. Instead of solace I found pandemonium. A bunch of hens were after Betty the Easter Egger and it was not a simple situation of grouchy old hens visiting random pecks on a lower ranking hen that gets too close. They had become a vigilante mob, and this was an all-out attack. I had seen this kind of mob violence before – it seems to happen when a hen becomes sick or debilitated. The hens of a nearly similar rank will often take advantage to eliminate her completely from the pecking order. I’d been noticing that Betty had been experiencing some leg weakness – it was getting hard for her to jump onto the roost. I was clueless as to what the cause was, but apparently the other hens decided that Betty’s time had come. Betty ran around the coop trying to escape the pecks of the other hens to no avail – they chased after her aiming hard pecks at her head and comb.

Emile the rooster showed up on the scene, as he always does when there’s a kerfuffle. He takes his job of maintaining peace and tranquility in his flock very seriously. Betty actually tried to crawl underneath Emile to escape the pecks of the other hens, which would have been comical had it not been so pathetic. Emile is a bantam roo, so there’s not a lot of space between Emile and the floor. I sighed, entered the coop, snatched up Betty and looked her over. She was bleeding in a couple of places on her comb from well-aimed pecks but otherwise she seemed to have escaped unscathed.

I put Betty in the small pen that had just become available because of Arlene’s sad passing. I had no long-range plan, but the immediate plan was that Betty could no longer go back into the coop because she would be brutalized by the other hens. She would have to live on her own.

Betty roosted in the small triangle pen that night and the next day I let her out of that small space and allowed her to roam the center part of the pole barn – and that became the routine. Whenever I was in the pole barn, Betty would follow me around like a lonely orphan puppy. Chickens live in flocks after all, and Betty only had herself – I’m sure she was lonely. Except for her leg weakness, she seemed fine. She was actually a beautiful bird. She was in her fifth year and while she hadn’t laid an egg for a couple of years she didn’t look like an old hen. She maintained an almost militarily erect posture, kept her feathers preened to a shine, and would strut around like she knew that she was a very pretty hen. I didn’t ever stop to think that maybe her posture was a little too erect for a hen and that her hackle feathers had become unusually elongated. And why didn’t I notice that her comb had become so large?

**Betty living on her own - here she roosts on her fancy John Deere roost, which coincidentally also functions as a mower.**

My roosters crow a lot. Why do they crow? The simplest answer: Because they’re roosters. For a more in-depth answer, read my post about why roosters crow. The roos usher in the morning by crowing and then there are random bouts of crowing throughout the day. At least it seems random to me—I’m sure the guys know exactly why they’re crowing. One day in early July I was working in the barn and the boys were going through one of their crowing cascades. Emile would proclaim his roosterhood, then Paul would add his two-cents-worth, and then Snowball would chime in from the other coop. In the midst of all that racket I gradually begin to wonder if another voice had added itself to the chorus. I tried to trace this new voice to its source, but when I rounded the protruding edge of Coop 2, the only bird standing in that sequestered corner was Betty. I looked at her and she looked at me, then she opened her beak wide and said, “Errrr-errr-errrrrrr!” Then it was my mouth that opened wide as my jaw dropped to hit the floor.

What makes a hen a hen and a rooster a rooster? You are no doubt familiar with the idea of XX and XY sex-determining chromosomes in humans – females have XX chromosomes and males have XY chromosomes. Chickens use a whole different set of chromosomes to determine sex – roosters are ZZ and hens are ZW. In normal chick development, the presence of the W gene causes the left “protogonad” in the developing chick to become an ovary (the right “protogonad” never develops and remains dormant). The production of estrogen by the left ovary causes the chicken’s body to develop hen-like characteristics – a smaller, rounder body, a small comb and wattles, shorter, blunter feathers, etc. Spontaneous sex reversal occurs in hens when something happens to the left ovary to shut off the estrogen supply. Scientists have demonstrated this phenomenon by surgically removing the ovary, but it can happen spontaneously when the ovary is damaged by a tumor or an infection. This is, apparently, what’s going on with Betty. Something is causing her leg weakness – a tumor pressing on a nerve perhaps? It seems likely that whatever is causing her leg weakness has also shut down her left ovary.

When the ovary shuts down and the flow of feminizing estrogen is shut off, the hen spontaneously begins to develop male characteristics – her comb and wattles will grow larger, and when she molts she will develop male-pattern feathers – longer and sharper hackle feathers and tail feathers, and in breeds where males have different color patterns than females, she will develop the color pattern of the roosters of her breed. She’ll also adopt rooster behavior, such as a more upright posture, and will start crowing.

**Betty juxtaposed with her Easter Egger hatch-mate, Veronica. Both hens are in their 5th year. Veronica still lays the occasional egg. Betty's life has taken a different path.**

Most amazingly, as this process continues, the dormant gonad on the right side of the hen’s body activates in the absence of estrogen and develops into a sex organ called an ovotestis. It has been demonstrated that an ovotestis can produce sperm but there are no known instances where a sexually reversed hen has fathered offspring.

Also, quite amazingly, there have been cases where the sex reversal was caused by a temporary phenomenon such as an infected ovary. And when the infection cleared up, the ovary began to produce estrogen again. So, when the next molt occurred, the hen molted back to her hen plumage. In certain of those cases, the hen began to lay eggs again prior to her molt - thus was laying eggs while decked out like a rooster. Perhaps it is this situation that has given rise to all the folk-tales of roosters laying eggs. In 1474, for example, a rooster in Basel, Switzerland was put on trial and found guilty of the unnatural act laying an egg and was then executed by burning at the stake. It was a fairly common thing, back in the day, to try animals in both ecclesiastical and secular courts – cows, horses, pigs, even rats and weevils had their day in court. And in the case of the rooster, everybody was fairly convinced that the egg was the spawn of Satan himself, and if the egg was then somehow incubated by a toad, a cockatrice or basilisk would hatch out, and that would be really bad news!

Betty is not going on trial. After spending nearly the entire summer living on alone, one day in September, pretty much on a whim, I cautiously put Betty in the coop with my six little pullets and waited to see who would attack whom. Well, good news: Nobody attacked anybody! They’ve all been living together peacefully now for several weeks. Very soon, the day will come when I introduce the pullets into the Coop 1 flock. Can I also reintroduce Betty? Stay tuned. Betty’s complete story is yet to be told.