When Snotlout brags of how his family never loses to Thawfest, we see Hookfang behind Snotlout without his saddle and the rest of his neck spikes are there. But when he flies off with Snotlout his saddle is back and his neck spikes are basically erased.
When Spitelout comes to talk to Snotlout before the race Hookfang has his saddle on without his neck spikes (as usual), but when Snotlout turns to face his dad Hookfang's saddle is gone and his neck spikes are back.
When Spitelout is talking to Snotlout the first shot of Snotlout he is near Hookfang's head, but after Spitelout says he's never lost a Thawfest game Snotlout is shown in front Hookfang's wing.