My girl has lost most her feathers on her underside and has a bad rash

[silkieroo]

Has she been spending a lot of time in the nesting box?? That kinda looks like broody baldness to me...

 

[PepsNick]

The OP has not mentioned broody behavior so I doubt it.

 

[snapkrackelpop19]

Nope she hasn't been broody at all, even tried to introduce the new chicks to her and she wouldn't have anything to do with them! lol. But I'm keeping her inside all nice and toasty warm while it heals

Its been really wet here so maybe the coops been damp and that may have a part?

 

[zazouse]

It's not gona clear up over night, you are may end up with a house guest for the next 3 to 6 weeks before she feathers out

It's not from the weather ,she is just molting