On ship notice pig brought in (6)
I believe the answer is:
aboard
'on ship' is the definition.
(I've seen this before)
'notice pig brought in' is the wordplay.
'notice' becomes 'ad' (both can mean an advertisement).
'pig' becomes 'boar' (I've seen this before).
'brought in' is an insertion indicator.
'ad' placed around 'boar' is 'ABOARD'.
(Other definitions for aboard that I've seen before include "on base" , "Part of the group" , "On an aircraft" , "... [CRUISE SHIP] here, perhaps" , "on deck" .)