Father eating bird finds bone (5)
I believe the answer is:
femur
'bone' is the definition.
(I know that femur is a type of long bone)
'father eating bird' is the wordplay.
'father' becomes 'fr' (abbreviation as in a priest's title).
'eating' indicates putting letters inside.
'bird' becomes 'emu' (emu is a type of bird).
'fr' going around 'emu' is 'FEMUR'.
'finds' acts as a link.
(Other definitions for femur that I've seen before include "bit of leg" , "Bone in leg" , "Part of leg" , "Thigh bone" , "Thighbone" .)