Brain Game: Prison Blues

Today's mentalfloss.com Brain Game Wednesday Wordplay challenge celebrates the return of AMC's The Walking Dead series this past Sunday with the first episode of Season 3. Good luck:

By changing one letter in each step to form English words, and leaving all other letters in their original positions, convert BITTEN into WALKER in the fewest possible steps.

B I T T E N
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W A L K E R