Playing their first competitive game for five weeks, Thornton showed some signs of ring-rustiness but still managed to run out comfortable winners.
There was an early scare for Craig Gilbert's men though when Paul Taylor rounded Ryan Linton but Matthew Robertson came to his side's rescue by clearing the ball off the line.
Chris Ireland gave the Hibs a 13th minute lead, heading home Daniel McNab's cross at the back post before the same duo combined to make it two in the 31st minute except on this occasion, Ireland headed the ball into the path for Ian Shanks to score just his second goal in over 100 appearances.
Ireland netted his second from the spot just two minutes later after Garry Thomson snr had been felled in the area.
Shortly before half-time, the Vics were denied a lifeline when Paul Taylor's shot from fully 30 yards crashed back off the crossbar.
Shanks showed he had got a taste for this goal-scoring malarkey by heading the fourth in the 74th minute and then substitute, Garry Thomson jnr drilled home the fifth four minutes later.
There were no more goals for the visitors but Scott Black did manage to grab a consolation for Brechin near the end.
GI Joinery Hibs' Man of the Match: Ian Shanks
Brechin Vics: Davidson, Milne, Stephen, Taylor, Johnston, Steel, Black, Mitchell, Hendry, Crowe, Ferries. Subs: Eaton, Young, Wood, Ferrar, O'Neill
Thornton Hibs: Linton, M.Robertson, McMillan, Drummond, Shanks, Coleman, McNab, Hepburn, Ireland, Thomson snr, Crichton. Subs: Keatings, Burns, Henderson, Strachan, Thomson jnr.
Referee: Mr R. Taylor
Match statistics:
Attempts at goal - BV 10 TH 16
Attempts on target - BV 3 TH 7
Corners - BV 1 TH 8
Offside - BV 0 TH 1
Fouls committed - BV 10 TH 9
Yellow Cards - BV 2 TH 1
Red Cards - BV 0 TH 0