I have a hen who has been laying about a month now. She's been laying great, and has acted very normal. Yesterday, I thought I noticed some lethargy. Today, she's spent much of the day alone. She's eaten little, but I have seen her drinking. Quite often I've watched her just nesting in a pile of leaves. But the strange thing we noticed was her neck feathers puffed out, almost as if there is inflammation in the neck. Once, for about 2 minutes, we noticed her shaking her head a bunch. She stopped that and hasn't done that again, but thought I'd mention it. She's a golden comet, less than 1 year old. There is no sneezing or fluid in the eyes or nostrils. Any idea what this might be?