Yellowing Comb & Waddle

[Somiskel]

The last few days I have noticed her feathers being super ruffled and puffed out, tail feathers down and her comb is yellow/pale. She isn't moving around much. Still eating and drinking. She is old, maybe 5 years of age. She is the only original one left from my first flock.
Is she suffering? Has anyone seen this in a hen before? I separated her today from the rest of the flock.

 

[oldhenlikesdogs]

She looks very sick, I would wither cull her because she looks to be suffering and because of her age, or find a vet to have a look at her.