First off, Willow is adorable!
Don't be surprised if you see a lot of posts telling you that Willow needs to be with other chickens and that she can't be happy in the house. I won't be one of the people who tells you that.
I ended up with a lone chick three Septembers ago, when a feed store employee "kindly" gave me the last layer chick in a brooder of broilers. The others were bigger than her, and she spent her time hiding in a corner or under the light fixture.
It was too late in the year for her to be brooded outdoors, and there weren't any other chicks available to put with her indoors. I tried to integrate her into one of my other coops, but I failed every time. She is terrified of other chickens --even my Welsummer, who was the lowest in the pecking order,
She is not scared of the house cat or the two rescue dogs, although she finds the larger one annoying. Dottie lives in a large dog crate in the dining room and is happy to go outside for field trips where she dust bathes with glee, pecks at the grass and chases bugs. Dottie also likes to "swing," but for her that means perching on the back of a rocking chair and making it go back and forth.
Dottie is not subjected to rainy weather, snowy days or predation. She seems perfectly content to be a house chicken and knows to perch on command when it's time to walk her out past the dogs.
She quickly learned to escape the rest of the flock by flying over the deck railing (most of my girls are too heavy or too lazy to try) and is the only chicken who plays on the north side of the fenced yard -- away from the birds that scare her.
Yes, chickens are flock animals, But they're also individuals. I wish Dottie could be part of a group, but she isn't. It's been her choice, really. Having a chicken living in the dining room puts a damper on dinner parties, for sure.
I hope Willow can become part of a flock, but if she can't or won't, it doesn't mean she's miserable. She may just be a loner who likes people better than other chickens.