Many of my snakes like to headrub food - it seems to be part of assessing if they want to eat an item or if it is indeed food at all. They do it more with dead and unfamiliar foods and when they are no longer ravenous, bu still sttuffing it in.
My checkered does it a lot- I thought kit might be poor (albino) vision but the Butlers do it also with fish and pink ppieces, but seldom with worms unless already stuffed,