henyoudaoicibaDictYouDict[hen 词源字典]
hen: [OE] Etymologically, a hen is a ‘singing bird’. The word goes back ultimately to a prehistoric Germanic *khanon ‘male fowl, cock’, which was related to the Latin verb canere ‘sing’ (source of English chant). In the West Germanic dialects a feminine form developed, *khannjō, which has become German henne, Dutch hen, Swedish höna, Danish høne, and English hen. (The original masculine form survives in German hahn, Dutch haan, and Swedish and Danish hane, but English has given it up – the Old English word was hana, and if it had survived to the present day it would probably be *hane.) The metaphorical extension of the term to any female bird took place in the 14th century.
=> chant[hen etymology, hen origin, 英语词源]
hen (n.)youdaoicibaDictYouDict
Old English henn, from West Germanic *hannjo (cognates: Old Frisian henn, Middle Dutch henne, Old High German henna), fem. of *han(e)ni "male fowl, cock" (source of Old English hana "cock"), literally "bird who sings (for sunrise)," from PIE root *kan- "to sing" (see chant).

The original masculine word survives in German (Hahn "cock"), Swedish, Danish, etc. German also has a generic form, Huhn, for either gender of the bird. Extension to "female of any bird species" is early 14c. in English. Hen as slang for "woman" dates from 1620s; hence hen party "gathering of women," first recorded 1887. To be mad as a wet hen is from 1823, but the figure was used to indicate other states:
Some, on the contrary, are viciously opposite to these, who act so tamely and so coldly, that when they ought to be angry, to thunder and lighten, as one may say, they are no fuller of Heat, than a wet Hen, as the Saying is; .... ["Life of Mr. Thomas Betterton," London, 1710]



Orth. Out upon you for a dastardly Fellow; you han't the Courage of a wet Hen. ["A Sermon Preached at St. Mary-le-Bow, March 27, 1704"]
As wanton as a wet hen is in "Scots Proverbs" (1813). Among Middle English proverbial expressions was nice as a nonne hen "over-refined, fastidiously wanton" (c. 1500); to singen so hen in snowe "sing miserably," literally "sing like a hen in snow" (c. 1200). Hen's teeth as a figure of scarceness is attested by 1838.