When Rebecca Johnson's husband died, the Maxwell, Iowa woman had to support three young children on her own. Cleaning houses and sewing did not pay enough, so Johnson used her small inheritance to buy a house, eight acres of land, two cows, a few pigs and several dozen hens. She raised chickens year-round, paying careful attention to their needs. She built a hen house that was so warm her hens laid eggs all winter. She later wrote, "I fed them cabbage, beets, turnips, squash, onions, for I knew to produce eggs in winter I would have to make conditions as near like those of the warmer months as possible… I never let them out on cold days."

Soon she made enough money selling eggs for 18 cents per dozen to pay her living expenses and feed her animals. In the late 1800s Rebecca made her first incubator.

She's a Success!

Using incubators, Rebecca hatched 5,000 chickens in one season. Later in her poultry career, she hatched half that amount in a single day! Eventually, she made $300 monthly during the busy part of the year. Newspapers wrote about her skills. She received so many letters asking for advice that she wrote a book. Rebecca published How to Hatch, Brood, Feed and Prevent Chicks from Dying in the Shell in 1906.

In 1907 Rebecca received U.S. Patent No. 894,835 for an incubator alarm. The device alerted farmers to changing temperatures within the incubator. Later, she refined her invention so the thermostat raised and lowered the wick of a heat lamp.


  • Katharine House, “Iowa Inventors A-Z,” The Goldfinch 20, no. 1 (Winter 1996): 4-10.