Speed of pigs eating paper at first seems surprising (9)
I believe the answer is:
swiftness
'speed' is the definition.
(synonyms)
'pigs eating paper at first seems surprising' is the wordplay.
'pigs' becomes 'swine' (I've seen this before).
'eating' indicates putting letters inside.
'paper' becomes 'FT' (newspaper the FT, Financial Times).
'at first' suggests taking the first letters.
The initial letters of 'seems surprising' is 'ss'.
'swine' placed around 'ft' is 'swiftne'.
'swiftne'+'ss'='SWIFTNESS'
'of' acts as a link.
(Other definitions for swiftness that I've seen before include "speed" , "Rapidity - as of fast bird?" .)