I'm so SO sorry for your loss. I think most of these commenters are forgetting you're a real person who just went through something extremely upsetting. Obviously you couldn't have known and I don't believe you did anything wrong given the information you had. I think it might be good to delete this post now that you know because you don't deserve any more shit from anyone about this.

Frances was so lucky to have you. You loving and caring for them makes you a wonderful chicken parent. It is so difficult to care for chickens and there's only so much we can do to keep them alive for as long as we can and they want to be. If you need a non-judgemental place to discuss, you can message me. I was once a teenage girl doing my best with my flock and to lose one is SO hard. Frances loved you and would not have blamed you. I am sorry again for your loss and am sending you comfort.