I'm glad to hear she is improving. You want her strong enough to be able to defend herself when she is integrated back with the others. If you feel that she needs more time or extra vitamins/nutrition, then by all means provide it.UPDATE:
She's curling all of her toes now, and is starting to walk more normal. She still is skinny, she felt like she put some weight on, but now it feels like either she hasn't improved since then or it's gone back a little since cutting back on all the supplements.
I have not noticed any sneezes in the last couple days, so I think she might be over that for now.
Should I just keep on keeping on and see how she does?
I'm starting to think about how introductions are going to go. It's getting pretty cold here, so I don't know if a fast transition would be better (because I can't leave her in a kennel in the run...its just too cold). She's also only had any experience in the front yard, so I don't know if it would be more stressful to carry her around back, and then return her to her kennel in the front. How long should a transition take?
Flock dynamics and re-integration can be a tricky thing, sometimes it may take just a day or so, while other times it can be a long drawn out process. Getting her acclimated to the temperatures would be a good place to start - can you place her near the others at least during the day so they can see her?
http://www.backyardchickens.com/a/introducing-a-single-hen-to-an-existing-flock