The following version of this book was used to create this study guide: Polzin, Jackie. Brood. New York: Doubleday, 2021.

The novel begins with the unnamed narrator remembering four years earlier when she had just gotten her four chickens. Her best friend Helen came to visit, and when the narrator placed an egg in Helen's hand, she did not know what to do with it. She notes that people often do not seem to understand that the eggs in the supermarket and an egg “fresh from a chicken” (3) are the same.

In the present, it is winter, and the narrator carefully controls the temperature in the coop so the chickens—called Miss Hennepin County, Darkness, Gloria, and Gam Gam—do not freeze. She feels like she misses the chickens even though she is still with them.

The narrator's husband, Percy, flies from their home in Minneapolis to Los Angeles to be interviewed for a professorship at a university and the narrator visits her mother to ask if she would be willing to take the chickens if they move away. Her mother agrees.

Helen asks the narrator to watch her one-year-old son Johnson while she goes to work. While Helen is gone, the narrator worries that Johnson has a fever. However, when Helen returns, she assures the narrator that Johnson is fine. The narrator notes that this kind of maternal intuition is something she has not experienced because she does not have children.

Helen is a realtor, and the narrator cleans the houses she is selling. While cleaning one particular house, the narrator recalls cleaning it once before six years earlier. She was four months pregnant at the time, and while cleaning she experienced a sudden intense pain and then miscarried.

One night, the narrator enters the coop to feed the chickens and discovers that Gam Gam is dead. The narrator and Percy take her to a veterinary hospital for an autopsy but the results are inconclusive. Percy tells the narrator that Gam Gam was his favorite chicken. She tells him she does not have a favorite, but this is not true. Gam Gam had been her favorite as well.

The narrator explains that both her house—which Percy bought with his ex-girlfriend—and her neighborhood are in a state of decline. The house has cracks in the walls and ceilings from the vibrations of the trains that frequently pass by and many other houses in the neighborhood are boarded up. She believes it is a good time to move.

The narrator and Percy are visited by some former neighbors—Cal, Lynn, and their young daughter Katherine. Katherine is fond of the chickens.

One night, Percy has a night terror and tells the narrator he felt like a woman was sitting on his chest. When asked how he knew it was a woman, he declares, “she had the aura of a woman” (80), which the narrator understands because she had known their baby was going to be a girl.

The narrator goes to a farm supply store and purchases new chicken feed. She wonders if Gam Gam died as a result of poor diet. Shortly thereafter, she enters the coop and finds Miss Hennepin County dead. It appears she was attacked by a predator.

The narrator goes to another farm supply store and buys new chicken feed again. While there, she watches as a mother and son adopt a chick. That night, she worries about the chick, wondering if the mother and child will take proper care of it.

She recalls asking Percy to tell Helen about her miscarriage shortly after it happened. Helen paid for the narrator to see a psychic who specialized in infertility. The psychic met her at a museum, where the narrator noticed a painting she had seen before. She had initially thought the woman in the painting looked happy, but seeing it again now, she thought the woman was overcome with grief.

A tornado hits while Percy is visiting the university in Los Angeles, having been officially offered the professorship. Darkness is left outside during the storm, but she survives unscathed. There is also a bird flu outbreak and the narrator worries about the remaining chickens' health.

The narrator takes Darkness to her mother's house so she can acclimate to caring for the chickens. The morning after she arrives, the narrator and her mother are in the kitchen when they see feathers float by the window. They go outside and discover Darkness has been killed by a predator.

The narrator visits Helen's house, and over dinner she watches Helen take a pistachio out of Johnson's mouth and eat it. She notes that she will never have this kind of experience because she cannot have children. She thinks she would have been a good mother.

A few nights later, the narrator is awoken by noises coming from the chicken coop. She and Percy go outside and scare a raccoon away, but when the narrator picks Gloria up, she discovers one of her eyes is missing.

The narrator decides she cannot leave Gloria with her mother because she is too attached to her. Helen tells the narrator that she is pregnant again. A short time later, Gloria goes missing and Percy discovers her body.

Helen sells the couple's house to a woman who is moving to be closer to her mother. Percy cleans the chicken coop and reconverts it to a garden shed. The narrator thinks it is almost as though the chickens never existed.