Help! Pale comb, purple comb, and droopiness!

[KlinoClucks]

Hey everyone,
I have a Faverolle hen who has been looking unwell lately. She has a very pale comb, and is reluctant to eat. Very quiet and prefers to keep to herself. I let her be and just watched her for a few weeks now, and although she isn't getting worse quickly, she seems to be declining slowly and is not getting better.
I have another Faverolle hen in the same flock who started losing feathers on her breast, but seemed fine and clucky. Then all of a sudden a few days ago she just, well, got sick. Pale comb, very inactive, just sits in the shed all day with her head tucked under her wing. It looks like the same thing the other one has, only much worse. We had a perfectly healthy hen in that coop die very unexpectedly (all good that morning, dead that afternoon), wondering if that might be something of concern?
In another flock (neighbouring this one) I have a Buff Sussex who had been looking unwell for a while as well, not active, and today her comb went light purple.
Not sure if all this is related or what it could be - any help or advice would be very much appreciated!

 

[KlinoClucks]

She tucks in her head like this and doesn't even move when I'm around

 

[KlinoClucks]

 

[KlinoClucks]

 

[Lizzy733]

Purple comb is generally lack of oxygen. Are the having any breathing difficulties? Wet or gunky nostrils? Breathing heavily?

Are your ill hens eating at all? Feverish? 105-107 is a chicken's normal body temp, so they will feel hot, but a feverish hen will feel 'very' hot. Might be a good idea to offer electrolytes or something like polyaid and I would recommend involving a vet since it's so many birds affected.

Not much you could do for viral, but antibiotics would help if it's bacterial. How's your weather? Any mildew or mold in the coop?

 

[KlinoClucks]

No trouble breathing, clear airways. They are eating a little - one or two pecks and then they've had enough. I can't feel that they are any warmer than usual - they have lost a considerable amount of weight (a scary amount, but only the two faverolles - buff sussex still looks good).
I'll see if I can find some antibiotics and see if that helps. There is no mould in the coop that I can see, but I'll give it a clean anyways and see if it helps. A spring clean is never a bad idea!
The weather is pretty cold and wet - maybe Faverolles just don't do well in the wet?