Fag end spawned by the pig-headed (8)
I believe the answer is:
stubborn
'the pig-headed' is the definition.
(I've seen this before)
'fag end spawned by' is the wordplay.
'fag end' becomes 'stub' (I've seen this before).
'spawned' becomes 'born' (I've seen this in another clue).
'by' is a charade indicator (letters next to each other).
'stub'+'born'='STUBBORN'
(Other definitions for stubborn that I've seen before include "small boat in Loire, good for going around river" , "Showing dogged determination" , "Inflexible" , "Strong-willed" , "Resistant to change" .)