You have mother hen to care for her chick is the best option, might be let her care for this chick and monitor, you might need to help here and there like you have been doing.
I am no expert, but I had mother hen hatched out eggs a handful of times.
I had 1 chick was the only egg and she was so weak and she was not able to break out of the eggshell herself, after 24 hours, I helped her to break out.
She was very weak, just flat out on her side with eye closed, made small weak sound not often. I was fearful that mother hen might stepped on her so I moved them into my kitchen to monitor only. Mother hen sheltered the weak baby chick, and after a day she was standing up but just very weakly and she is now almost a year old, trouble maker, escape artist and demanding.
I wish your baby chick get stronger, it is good that mother hen is there.
Edit to add: If mother hen does not accept her, it will be very bad for the chick. Like Casportpony says might be put her back in the incubator
