rare/scarce as hen's teeth

(as) rare as hens' teeth

Incredibly scarce or rare; extremely difficult or impossible to find. Support for the president is as rare as hens' teeth in this part of the country.
See also: rare, teeth
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

*scarce as hen's teeth

 and scarcer than hen's teeth
Cliché scarce; seldom found. (*Also: as ~.) I do declare, decent people are as scarce as hen's teeth in these chaotic times. Handmade lace is scarcer than hen's teeth; most lace is made by machine.
See also: scarce, teeth
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.

scarce as hen's teeth

Also, scarcer than hen's teeth. Exceptionally rare, as in On a rainy night, taxis are as scarce as hen's teeth. Since hens have no teeth, this term in effect says that something is so scarce as to be nonexistent. [Mid-1800s]
See also: scarce, teeth
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

rare as hen's teeth

or

scarce as hen's teeth

OLD-FASHIONED
If something is as rare as hen's teeth or as scarce as hen's teeth, it is extremely rare. Record companies are becoming as rare as hen's teeth. Note: Hens do not have teeth.
See also: rare, teeth
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012

rare (or scarce) as hen's teeth

extremely rare.
As hens do not possess teeth, the implication is that something is rare to the point of non-existence. The phrase was originally a US colloquialism, dating from the mid 19th century.
See also: rare, teeth
Farlex Partner Idioms Dictionary © Farlex 2017

(as) rare/scarce as hen’s ˈteeth

(old-fashioned) extremely rare: Critics always complain that good movies that the whole family can see together are as scarce as hen’s teeth.
This refers to the fact that hens do not have teeth.
See also: rare, scarce, teeth
Farlex Partner Idioms Dictionary © Farlex 2017

scarce as hen's teeth

Singularly rare. Also put as scarcer than hen’s teeth, this allusion to nonexistent dentition is an Americanism of the nineteenth century. It appeared in James Gilmore’s My Southern Friends (1863): “Horses are scarcer than hen’s teeth around here.”
See also: scarce, teeth
The Dictionary of Clichés by Christine Ammer Copyright © 2013 by Christine Ammer

scarce as hen's teeth

Nonexistent. Hens have no teeth, so what could possibly be scarcer? (Stones in their gizzards act as teeth to grind their food).
See also: scarce, teeth
Endangered Phrases by Steven D. Price Copyright © 2011 by Steven D. Price
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