I think you mean the MC kills the creatures for others and thus earns the money to put the chicken on the table. To me, a girl has got to make a living. As long as she stops once she sees the truth of what she's been paid to do, I'm okay with it. She isn't evil, the system/world she's caught up in might be. I assume she fights that evil. I'm reminded of Katniss who has to kill to survive and to change her world.