Flier, dead at heart, gets leg broken (5)
I believe the answer is:
eagle
'flier' is the definition.
(eagle is a kind of birdanimal)
'dead at heart gets leg broken' is the wordplay.
'at heart' says to take the centre.
'gets' is a charade indicator (letters next to each other).
'broken' is an anagram indicator.
The middle letters of 'dead' are 'ea'.
'leg' anagrammed gives 'gle'.
'ea'+'gle'='EAGLE'
(Other definitions for eagle that I've seen before include "somewhat under par" , "Bird of prey, may be golden" , "Hook-billed bird of prey -- old US $10 coin" , "Old comic" , "Keen-sighted bird of prey" .)