Crow loses tail and several feathers around neck (4)
I believe the answer is:
'several feathers around neck' is the definition.
(feathery neck garment)
'crow loses tail' is the wordplay.
'crow' becomes 'boast' (I've seen this before).
'loses tail' means to remove the last letter.
'boast' with its final letter removed is 'BOAS'.
'and' acts as a link.
(Other definitions for boas that I've seen before include "21 [SNAKES]", "Long fluffy scarves of feathers", "Large snakes", "Cold-blooded creatures".)