I have a dwarf/mini (I don't know the correct word in English) silkie hen, she's around 3 years old. She always used to be gentle and friendly, but she never acted this way before. All she does all day (for weeks now) is just laying on/at random places around the yard, she's not walking together with the other hens, but her appetite isn't gone and she's still just as heavy (she's not overweight, just the same weight she always had) as she always was. She doesn't have any problems while she walks, there's also no visible problem on her legs, I checked them. The only other problem I see is her back (at her tail), it's "worn" (I'm sorry if it isn't the right word for it). We only have two roosters but they're not around her 24/7, we have many many hens so she's not a targeted hen for the roosters. She always used to have beautiful feathers/fur and she was always a social hen but she changed.
Is there anything I can do for her? Honestly there are no vets who can cure chickens in my area, so that's why I'm hoping I can get a little help here. Of course if it's needed, I will call a vet for her.
Thank you so much in advance.