Awww...Sweetie!You guys have all been so nice. Thank you. I was honestly a little worried about what kinda replies I was gonna get but obviously I've had no reason to worry at all. She's eating and drinking well, and back in with the flock because you're right I think it was just malnutrition again. She even went into the coop all by herself when before I always had to lift her in. The poor thing had feathers growing directly down over her eyes!
Still working on the ventilation. There's no smell of ammonia coming out of the coop at all and I haven't cleaned for a week. That's why I originally thought I didn't need more ventilation, but I guess no ammonia doesn't really mean anything?

No need to worry, we will try to help you the best we can, if we can't figure it out, we will at least try to give you a word of encouragement.
So glad to hear she is eating and drinking! She made it into the coop all by herself too!
I call that progress

It's good there is not an ammonia smell, keeping the coop cleaned will help, but as @ChickenCanoe mentioned, try to get the ventilation fixed as soon as you can. Fresh air is very important to chicken health.
@oldhenlikesdogs gave you good advice. Stay on top of keeping those feathers trimmed so she can see!
I hope she continues to do well! Keep us posted.