“Mad as a wet hen” (very mad)

To be “madder than a wet hen” or “as mad as a wet hen” is be to very mad. Hens don’t like water on their feathers.
   
“Mad as a wet hen” was printed in Spirit of the Times (New York, NY) on March 21, 1840. “Madder than a wet hen” was printed in the Democratic Free Press (Detroit, MI) on January 29, 1846.
   
     
21 March 1840, Spirit of the Times (New York, NY), pg. 25, col. 1:
Everybody should read the article, for the Notion pedlar being mad as a wet hen, the way he gives us “goss” is equal to cats-a-fighting.
   
30 January 1841, Spirit of the Times (New York, NY), “Mobile (Ala.) Races, Bascombe Course,” pg. 571, col. 1:
Just imagine the feelings of Mango’s friends, each looked as “a perfect case,” and as mad as a wet hen.
   
Chronicling America
18 February 1843, Louisville (MS) Messenger, pg. 2, col. 1:
Our brother typo of the Attala Gazette, seems to be disposed to take up the cudgel on behalf of the Wolf county paper, and says we are as mad as a wet hen. If he will inform us how mad wet hens generally are in Attala County, we shall be prepared to inform him whether his assertion is correct or not.
     
9 August 1845, Spirit of the Times (New York, NY), “To Correspondents,” pg. 273, col. 1:
The Captain is as mad as a wet hen, in consequence of not receiving his “warning” of the event.
 
29 January 1846, Democratic Free Press (Detroit, MI), pg. 2, col. 4:   
“Bill, what’s madder than a wet hen stuck in the fence?”
“I give up—I’s took.”
“Two of ‘em child.”
“Guess you’ve been studying addition hav’nt you?”
 
18 September 1878, New-York (NY) Daily Tribune, “Political Notes,” pg. 4, col. 5:
Massachusetts is a good deal madder than a wet hen.
 
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September 1896, The American Angler, “Current Comments,” pg. 314:
My young friend, Dick Hardenburgh, whom I met a few days ago on his return from a trip to Raritan Bay, was madder than a wet hen.
 
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July 1922, Munsey’s Magazine, “Use Common Sense” by Ellis Parker Butler, pg. 210:
He invariably caught the eight o’clock train, and now he had missed it, because his wife had insisted that he should carry this outrageous parcel to the express office. He was mad as a wet hen. He was madder than a wet hen, because he was mad all through, and spurting madness.
   
Google Books
White Waters and Black
By Gordon MacCreagh
Garden City, NY: Doubleday
1961
Pg. 137:
Perhaps the only thing madder than a wet hen is a wet statistician.
 
Urban Dictionary
Madder than a wet hen
Used in common phrases by rednecks/ white trash. It means to be madder than a wet hen, and when a hen gets wet; it gets really mad. The term cannot be said the way it looks though. You have to break it up all redneck like. Such as the example.
Jim: Whats up buddy?
You: Man, im madderd n a wet hen! (madder than a wet hen)
#[redneck#hick#stupid#mad#furious]
by Redneck Guy June 13, 2010
       
Business Insider
13 Southern Sayings That The Rest Of America Won’t Understand
Christina Sterbenz and Rylan Miller Oct. 31, 2013, 7:32 PM
(...)
2. “She was madder than a wet hen.”
Hens sometimes enter a phase of ” broodiness” — they’ll stop at nothing to incubate their eggs and get agitated when farmers try to collect them. Farmers used to dunk hens in cold water to “break” their broodiness.
 
You don’t want to be around a hormonal hen after she’s had an ice bath.
 
HuffPost
BOOKS 06/27/2014 07:33 am ET Updated Jun 28, 2014
11 Texan Phrases The Rest Of The Country Should Adopt
(...)
“I’m madder than a wet hen!”
Translation: “I am very mad!”
Example: “My daughter’s peculiar new boyfriend is a vegetarian. He was madder than a wet hen when I served brisket at dinner just to spite him. Ha ha!”
 
Google Books
Title She’s Madder Than a Wet Hen: 2019 Weekly Planner Journal Gift for Sarcastic Southern Friends and Family
Author Spitfire Books
Publisher CreateSpace Independent Publishing Platform, 2018
ISBN 1729767567, 9781729767566
Length 104 pages