Conjecture about origins of the latest chicken (7)
I believe the answer is:
gutless
'chicken' is the definition.
(thesaurus)
'conjecture about origins of the latest' is the wordplay.
'conjecture' becomes 'guess' ('guess' can be a synonym of 'conjecture').
'about' indicates putting letters inside.
'origins of' suggests taking the first letters.
The first letters of 'the latest' is 'tl'.
'guess' going around 'tl' is 'GUTLESS'.
(Other definitions for gutless that I've seen before include "Perhaps trim" , "Lacking courage and determination" , "Yellow" , "lacking a beer belly?" , "racket like this is not much use" .)