I replied to your other post about her diet, then I saw this one. Please look up info on gape worms and see if you think she may have them. If she does, it's easily treated, but must be treated. Florida is parasite heaven.
Chickens are social, but it sounds like the reasons she's not laying are physical. Between poor diet and possible internal parasites, she's got ample reason to not be laying yet.
The other possible reason for having her beak open like she's panting, is she could be too warm, but you say it's been very cool lately, so I doubt that's it.
Once you new chicks are feathered, you can put them out with her. Just keep a lamp for warmth where they can gather if they need to. I'd make sure she's free of parasites first, though.