After Winterfell is seized by ironborn raiders led by Theon Greyjoy, Farlen is among the members of the Stark household forcibly assembled at the castle's yard to witness Prince Bran's official yielding to Theon. Farlen refuses to serve Theon, and insists he's a servant of House Stark. One of the ironborn raiders, Drennan, beats him over the head with a club. He is helped up off the ground by his daughter Palla. They are both present when Theon Greyjoy assembles the people after the escape of Bran and Rickon Stark and unveils two charred corpses and hangs them up on either side of the castle gates.
In A Song of Ice and Fire, Farlen is also the loyal kennelmaster of Winterfell. It was not him but Mikken the blacksmith who talked defiantly to Theon Greyjoy, and was killed for that. Farlen was falsely accused by Theon of killing three of the ironborn (who were actually killed by Ramsay Snow at Theon's command), and was beheaded by Theon. In the TV series, he was replaced by Ser Rodrik Cassel at the execution scene.