hen night

[Everitt]

where does phrase 'hen' night come from

[Grunty]

Hens are female and hen parties are for females.  I expect the automated censor would have deleted my second sentence involving the male equivalent of hen, which I understand is not allowed at a hen party.

[Quizmonster]

Women have been referred to as 'hens' since the 1600s and the phrase 'hen party' first appeared in the late 19th century. 'Hen night' is just a more recent development of that.
The male equivalent is a stag party/night rather than a male-bird party!

[delboy3]

and then they get married and hen-peck their husbands...

[Quizmonkey]

A load of cackling females acting as if they have brains the size of peas - need you ask?

[Ouisch]

What exactly is a hen night?  Is it closer to a bridal shower or bachelorette party? 

[Quizmonster]

It's a girls' night out, Ouisch, drinking and partying. Originally, it was often before a marriage but really for any reason whatever nowadays.

[Ouisch]

Aha, thanks, Quiz!  Sounds like a bachelorette party - lots of drinking, noise-making, and the occasional male stripper.  :)