Sorry to piggyback with a similar problem but I've got one that has started puffing up and standing about with her head almost lost in her neck feathers the last few days. She's been here a month or so and still goes in and out the coop, seeks shelter etc and currently gets out in the garden 12 hours a day but is relatively inactive compared to the very busy other ones, tho I have seen her drinking and eating to some degree. She follows the rest out in the morning and back in to the run at about this time when I'm feeding corn, but just doesn't go for the grain which I'm a bit worried about, the rest go mad for corn and I'm not sure how much she is eating compared to them as the feeder is ad lib.
I'm assuming the dire weather is a major factor, so rather than keep them in the pen til lunchtime, I started letting them all out in the garden as soon as I get up so they can choose where to shelter from the driving sleet, snow, rain etc and the rest are thriving other than the pecking I mentioned elsewhere.
Other than control weather, am I making things worse letting them out 6-7 hours earlier these last 4 days and disrupting a routine they'd got used to? It's just been so snowy and muddy in there that I thought they'd be happier roaming.
I bought a tonic/supplement to add to the water and assume the rest won't mind getting it, and I'm looking into getting them all a bag of the medicated wormer feed from Marriages anyway but it's just this one hen - she's a big strapping one not a weedy skinny one and not one that has been getting pecked either.