Make sure all your birds are dewormed.
It could be respiratory.
Check her for gape worm and make sure her crop is flat in the morning. Even though she isn't laying yet, check her anyway for egg bound. Rule it all out. You can use a q-tip to go into her throat, if there is worms, you will see them on the q-tip.
Can you post a video. If your feeling maybe a reaction, stop the meds and see how she is doing over a few days.
When my birds died, they would breath with an open and closed mouth towards the end. Although it doesn't sound like that is going on.
The spots on her legs is puzzling.
It could be respiratory.
Check her for gape worm and make sure her crop is flat in the morning. Even though she isn't laying yet, check her anyway for egg bound. Rule it all out. You can use a q-tip to go into her throat, if there is worms, you will see them on the q-tip.
Can you post a video. If your feeling maybe a reaction, stop the meds and see how she is doing over a few days.
When my birds died, they would breath with an open and closed mouth towards the end. Although it doesn't sound like that is going on.
The spots on her legs is puzzling.