Adam Le Fondre opened the scoring from the penalty spot for the Premier League new boys after Aaron Downes had tripped Noel Hunt.
Le Fondre doubled his and Reading's tally just before the interval having been put through by Kaspars Gorkss.
Michail Antonio bagged the third after the break before Church struck twice, with a header and a close-range strike after Jason Roberts' shot was saved.
A minute later Jordan Obita's left-footed strike made it six before Church completed his treble with a low shot 20 minutes from time.
