Very large turkey to start, full-flavoured bird (7)
I believe the answer is:
ostrich
'bird' is the definition.
(I know that ostrich is a bird)
'very large turkey to start full-flavoured' is the wordplay.
'very large' becomes 'os' (abbreviation for oversize).
'to start' suggests taking the first letters.
'full-flavoured' becomes 'rich' (I've seen this before).
The initial letter of 'turkey' is 't'.
'os'+'t'+'rich'='OSTRICH'
(Other definitions for ostrich that I've seen before include "One refusing to face facts; flightless African bird" , "Denier" , "with a big nest egg" , "Someone unprepared to face the facts" , "World's largest bird" .)