Ate leg after cooking small bird (6)
I believe the answer is:
eaglet
'small bird' is the definition.
'eaglet' can be an answer for 'bird' (I have seen 'Young bird ' mean 'eaglet' so perhaps 'bird' could also mean 'eaglet'). I am not certain of the 'small' bit.
'ate leg after cooking' is the wordplay.
'after cooking' indicates an anagram.
'ate'+'leg'='ateleg'
'ateleg' is an anagram of 'EAGLET'.
Can you help me to learn more?
(Other definitions for eaglet that I've seen before include "A young raptor" , "Fledgling" , "One hatched in eyrie" , "Eyrie resident" , "another of the golden generation?" .)