Dogs got surrounded by pigs (7)
I believe the answer is:
shadows
'dogs' is the definition.
(I've seen this before)
'got surrounded by pigs' is the wordplay.
'got' becomes 'had' (having is a kind of getting).
'surrounded by' indicates putting letters inside.
'pigs' becomes 'sows' (I've seen this before).
'had' going inside 'sows' is 'SHADOWS'.
(Other definitions for shadows that I've seen before include "They're cast by blocking the sun" , "Follows" , "1960s band" , "tracks" , "Dark areas where the light is blocked" .)