“Never work with children or animals” is an old show business adage. Children and animals can behave unpredictably on the stage or movie set. Once the movie is made, the audience always looks for the adorable young child or animal—they steal every scene. ““Many stars will never appear with animals or children in the belief that no adult can compete” has been cited in print since 1931, in a newspaper article indicating that this film tradition carried over from the stage.
 
At a “roast” dinner for the actor-comedian W. C. Fields at the Masquer’s Club in Hollywood in 1939, the writer Leo Rosten said, “The only thing I can say about W. C. Fields…is this: Any man who hates dogs and babies can’t be all bad.” Fields is often credited with this and “never work with children or animals,” but neither saying can be originally credited to him.
 
   
Wikiquote: W. C. Fields
W. C. Fields (29 January 1880 – 25 December 1946), born William Claude Dukenfield, was an American Actor and Comedian.
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Misattributed
Anyone who hates children and dogs can’t be all bad.
. Although a very commonly attributed to Fields himself, this is derived from a statement which was actually first said about him by Leo Rosten during a “roast” at the Masquer’s Club in Hollywood in 1939, as Rosten explains in his book, The Power of Positive Nonsense (1977) “The only thing I can say about W. C. Fields ... is this: Any man who hates dogs and babies can’t be all bad.”
. Variant: Anyone who hates babies and dogs can’t be all bad.
 
Television Tropes & Idioms
Never Work With Children Or Animals
“Never work with children or animals.”
— W.C. Fields (attributed)
 
Google News Archive
29 November 1931, Milwaukee (WI) Journal, Stage, Screen and Fashions, pg. 4, col. 4:
Stage Traditions
Fall Before Films
Stage traditions many centuries old are dying rapidly under the influence of the motion picture, says Stuart Walker, for 20 years a stage director and little theater exponent.
(...)
“Many stars will never appear with animals or children in the belief that no adult can compete. But it is a mighty weak star who can’t dominate a performance.”
 
14 November 1950, The Times-Picayune (New Orleans, LA), “Looking at Hollywood” by Hedda Hopper, pg. 13, col. 5:
Many movie stars refuse to act with dogs or babies.
 
Google News Archive
17 January 1953, The Spokesman-Review (Spokane, WA), “Mary Dressler, Mary Garden, Intrigue Hedda” by Hedda Hopper, pg. 5, col. 5:
Stars today yell “Foul!” when they’re made to work with babies or dogs.
   
19 September 1959, Oregonian (Portland, OR), “Behind the Mike” by B. Mike, sec. 3, pg. 4, col. 1:
“I’LL PROBABLY LEARN what I’ve been told all my life—never work with animals or children. The dog will steal the show.”
(Ed Wynn—ed.)
 
Google Books
19 January 1968, Life magazine, pg. 76, col. 4:
“Every actor knows better than to appear with animals or children,” growled 27-year-old Oliver Reed, an actor who plays the part of Bill Sykes. “So here I am with a bloody dog and all these kids!”
(The movie Oliver!—ed.)
 
Google Books
Why Do We Quote?
By Nigel Rees
London: Blandford Press
1989
Pg. 38:
Never work with CHILDREN or animals
This is a well-known piece of show business lore, from American vaudeville originally, I should think. Phyllis Hartnoll, in Plays and Players (1985), has, “W. C. Fields is quoted as saying, ‘Never act with animals or children.’” Although this line reflects his known views, I suspect the attribution may result from confusion with “Any man who hates dogs and babies can’t be all bad” (which he didn’t say either: it was said by Leo Rosten about him at a dinner in 1939).
 
OCLC WorldCat record
PORTRAITURE - Never work with children or animals. This old maxim does not apply to three photographers who specialise in dog photography. Darron Hartas, tracks them down and retrieves the facts.
Author: Darron Hartas
Publisher: London : H. Greenwood, 1860-
Edition/Format:  Article : English
Publication: The British journal of photography. no. 7087, (1996): 16
Database: ArticleFirst
 
OCLC WorldCat record
Never work with children or animals.
Author: John Stirling
Publisher: Memoirs, 2010.
Edition/Format:  Book : English
Summary: John Stirling followed his parent’s footsteps into a theatrical career while he was still in short trousers. John’s life changed forever in 1989 when he and his wife were moved by pity to rescue two abused donkeys. This book tells the story of his life in the entertainment business, and of the events that led to his taking up the donkeys’ cause