I do not have to love or even like the protagonist in a novel. A perfect example of this is Perfume - a novel I liked quite a lot, despite the protagonist being a hideously vile person with no redeeming qualities, no reason whatever to root for him. I appreciate novels where the villain is given qualities or a history of what you can at least somewhat reasonably understand why she acts the way she does though you could never support her actions.
But even if I don't like the protagonist, I have to at least care about the outcome of their story. Whether they'll be redeemed or punished or karma-spanked. If I don't care about what happens to them, then what's the point of finishing their story?
Which is why I stopped Breaking Wild at around the 52% mark. Really, you could argue that this novel has two protagonists and their stories are presented in alternating chapters, with staggered timelines. There's Amy Raye, a bow hunter who has gone missing on a mountainside, and Pru, a search and rescue woman helping to look for her. Pru, I found somewhat engaging, though quite not enough to carry the story on her own.
Amy Raye, though... ugh. No thanks. I often find many protagonists start out somewhat reprehensible but they grow on me as their situation and history and motivations are slowly revealed (i.e. everything I've read by Gillian Flynn). Amy Raye was reversed for me - the more I heard of her motivations and backstory made me like her less, every chapter. Which made me care less about her fate, every chapter. And finally, I had to stop.
A caveat: I have read reviews from other readers saying that this wasn't the case for them - that they grew to like Amy Raye. So you may, too. If so, I can certainly say that the plot is quite engaging, pulling the reader right along to find out what's happened, and the disjointed time between the two women's stories serves this very well.
*Berkley Publishing provided an advanced copy for my review.