It is a synonym of
hoe.
It is a way to call a slutty, nappy,
hot, bitchy, or
whatever kind of girl you really want a hoe with out directly saying it.
Also, to further emphasize calling her a crow, you can begin to crow at her like a crow using a high pitched "RAAAAA, RAAAA" noise. As note, it is best to crow at them when they are passing by.
*
sees hot girl* "Check out that crow!"
or
*
sees nappy bitch walkin by* "RAAAAAA, RAAAAAAA"
or
"that
chick is shakin it like a crow"