Silkie pullet won't eat/drink, sits in corner alone

[ForTheLoveOfSilkies]

5 days ago I noticed my 4 month old Silkie pullet was sitting down in a corner and wasn't interested in eating or drinking so I took her in my house and over 4 nights she improved. She was eating and drinking and seemed normal. So I put her back with my other 20 silkies and she just sat in a corner again and wasn't interested in eating or drinking! Or moving!
I picked her up and put her beside the food and water but she wasn't interested, just walked away and sat down.
Other chickens didn't peck her or anything when I put her back so doesn't seem to be bullying.
Any ideas!?

 

[ForTheLoveOfSilkies]

Pic of 'Lucky'. I had her outside sometimes but in my house at night.

 

[chrissynemetz]

How is she doing now? Did she get better?

 

[ForTheLoveOfSilkies]

Hi, yes she is going well now. After a week in our house with multivitamin water and extra tlc she was eating and drinking and pooping all good and putting on weight so I put her back with the others. She is a very shy girl though and hangs out in the coop area all day even though I try to encourage her to go out to the grass with the others she runs back to safety of the coop. She has food and water and dust bath area and some dirt to scratch there so I guess it's ok she stays there? Door is always open for her to come and go if she wanted anyway.