hens' teeth

Something very scarce (because hens have no teeth). Typically used in phrases like "rarer than hens' teeth." I can hardly believe your brother got an A on his final exam—grades like that are rarer than hens' teeth for him!

Common Names:

Name	Pronounced	Usage
Morta	-	Lithuanian
Moritz	MO-rits	German
Kaja (1)	KAH-yah (Swedish, Estonian)	Norwegian, Danish, Swedish, Estonian, Slovene
Muireann	-	Irish
Trees	TRAY:S (Dutch)	Dutch, Limburgish
Tracee	TRAY-see	English