Stage at which, sadly, Hugh's retirement starts – no chicken! (7)
I believe the answer is:
leghorn
'chicken' is the definition.
(I've seen this before)
'stage at which sadly hugh's retirement starts no' is the wordplay.
'stage' becomes 'leg' (a leg is a stage of a competition).
'at which' means one lot of letters go next to another.
'sadly' is an anagram indicator.
'starts' says to take the initial letters.
The first letters of 'hughs retirement' is 'hr'.
'hr'+'no'='hrno'
'hrno' with letters rearranged gives 'horn'.
'leg'+'horn'='LEGHORN'
(Other definitions for leghorn that I've seen before include "port" , "Breed of domestic foul" , "Breed of chicken" , "Chicken; straw hat" .)