BoGoWo wrote:strip off the 'jargon'; what's a hen night'?
A "hen night" is when a party of ladies, females, go out on the razz together.
Originally I think, the female equivalent of a "stag night", but nowadays I think there does not have to be an imminent wedding for one of them: but I may be wrong about that part.
So, a group of like-minded females, out on the town. That's a hen night.