What is a person if they are described as a "wet hen"?
Solution 1:
In context, I took the phrase to mean dull, drab, a party-pooper.
Then I found this citation:
- [p. 159/139] "'That's 'cos you're a wet hen, Magrat Garlick,' said Granny."
When questioned about the phrase, Terry explained: "Perfectly good British slang. A 'wet hen' is bedraggled, sad and useless. Probably not as useless as a big girl's blouse, though, and better off than a lame duck."
Solution 2:
Not sure it would be used with the same meaning here... But in french a 'wet hen' (poule mouillée) is common expression for a wuss or a weakling...