thanks so muchI wouldn't worry too much about calcium then, I'd still keep oyster shells and grit available for her to pick at as and when she needs to top up on her calcium- but if theres no issue with her shells then I wouldn't worry about dosing her with calcium.
I would be reluctant to alter her diet too much while she is on antibiotics
The good news is that lighting changes alone can work well if you stick with the routine, it might take a bit of time but it should have the same effect.