Who knows if they'll go that far.
Scholastic released the first two books, and when the sales were ok, they went ahead up to book 8, which is coming out in September. As far as I know, Wikipedia or Seerowpedia has confirmed that Scholastic will go up to book 11 - The Forgotten.
and although this is unlikely, it would be kind of cool if we saw the human become the hawk, and then the hawk becoming the rabbit (for book 23, seeing as how book 13 might as well be the reverse of book 3 if it's the same model and the hawk looks the same)