I would like to know this too. I have a pullet doing the same type of thing. Not lethargic, though. I think thats the wrong word... Since I've been on an egg watch this week, all seemed normal, the squat, and all. And I've been out to the run every few hours. Usually I can count on my 8 pullets running up to the fence just to see what I'm bringing them! But when I went down this evening, my LBrahma just stood under the coop - it looked like she was holding her back/tail feathers up a little?
Anyway, she didn't really move, but wasn't sitting down. She didn't seem distressed, just... uninterested in what the others were doing and what goodies I had in tow. She's a top bird (in the peck. order) and its unlike her to be so... still.. and not fight for her portion of the scraps. She did seem to kind of trance out and close her eyes... maybe lethargic is the right word, but based on how often I've been checking, it would be sudden onset whatever it is... It has been hot here, but this afternoon was not so bad (shady, nice breeze), and I have seen her eat and drink today, though I haven't been able to tell how much, really.
Does anyone have any clues? Can she be egg boung after only laying an egg or two? She's right in the middle of figuring this whole egg laying business, and its been a week since our first, and last egg....