Hello! I am deseperate for some advice. A few of my sweet little hens don't seem to be doing well...They just turned 2 on April 1st, and I didn't get them until just this past November. They have a very large coup (there are 8 in total, no rooster), plenty of space in their run, they get clean water every day, they get oats and corn scratch, compost (no meat, coffee grounds, excessive fruit, but I don't pick out raw potato, avocado, and raw beans/peas). They are fed organic feed (pellets), the straw and hay is organic, and I don't give them any sorts of medications. They have a small covered area in thier run that was just recently built to keep some area dry for dusting, although it is still dry (live in Pacific Northwest, rainy!). In the past week I have noticed changes in one of the chickens, and today it has become worrying...
Here are the symptoms, starting with the one I am most concerned about...
Flopsy: Named from her "Flopsy" crest, which is fallen to the left. In the past she has always been very loud and vocal, but recently she has been standing away from her sisters and quiet. Today as I was watching her asking her why she wasn't part of the group anymore I noticed that she was shaking. I picked her up, which I don't often do to her because she doesn't like it, and I realized how very thin she was. I have noticed a few of the chickens seem significantly thinner than others. She is now hiding under the laying boxes in the coop, standing there unmoved with dropping eyelids. I want to help her!!
Scarlet: She was the best looking when I got them (they were molting), and now she is pretty mangy...The feathers on top of her head haven't come back, so she looks sort of bald. She also seems thinner than the others.
Fluffy Butt: She looks great, except that now her crest is starting to flop over to the right, which it never did before.

Can anyone please give me some answers?? I would greatly apprieciate it!!