Last June I had a rookie Brahma hen who hatched just one chick which she accidentally smothered. She could not cope with the flock (particularly the roosters) when i tried to re-integrate her.She stayed put in the agricultural shed, hiding in her broody pen if ever the door was opened for too long and the others came in.
Several re-integration attempts were unsuccessful. I gave up and left her in the agricultural shed (a huge structure for livestock and with several storage and workshop areas) where she happily pottered around all day, laying in the broody pen.
Yesterday, and 8 months after she went in there, the doors are opened to bring out some hay. Out comes Bluey. The initial 'unwanted attention' from 2 of the roosters seemed like it would send her back in the shed, but no. The first rooster mated her, the second she saw off, then she swaggered over to the other hens, pecked one who went for the bit of food the wanted, and stayed out all day. When nightfall came, she followed the others to the big coop.
I don't know why she decided yesterday was the day to rejoin the others, but I have given up trying to understand hen behaviour.