Oddly cool about sketch of chicken (6)
I believe the answer is:
coward
'chicken' is the definition.
('coward' can be similar in meaning to 'chicken')
'oddly cool about sketch' is the wordplay.
'oddly' means one should take alternating letters.
'about' says the letters should be written in reverse.
'sketch' becomes 'draw' (I've seen this before).
The alternate letters of 'cool' are 'co'.
'draw' written backwards gives 'ward'.
'co'+'ward'='COWARD'
'of' is the link.
(Other definitions for coward that I've seen before include "Noel -, twentieth-century actor, dramatist" , "who lacks guts?" , "Person without courage" , "Noel ..... composed musical 'Bitter Sweet'" , "One lacks courage" .)