Actually it's a fake news story about what started the fire as no investigation ever concluded that the cow kicking over a lantern was the cause as is the commonly held belief.
I am often telling people who mostly don't want to agree, admit to or otherwise that the news has always been fake news.
It turns out that the story of Mrs O'learys cow was a fabrication by a small group of newspaper reporters. Which they used to also whip up anti-Irish sentiment in the city.
I think you can begin to read about the real story from using this,
"Michael Ahern, last surviving reporter of the famous Chicago fire of 1871, and who denied the authenticity of the story of Mrs. O'Leary's famous cow which was credited with kicking over a lamp in a barn and starting the fire, died here tonight.
"In 1921, Ahern, in writing an anniversary story of the fire said that he and two other reporters, John English and Jim Haynie, concocted the explanation of the cow starting the fire, and admitted that he afterward learned that spontaneous combustion of hay in the O'Leary barn probably was the cause. At the time of the fire Ahern was a police reporter for The Chicago Republican."
