I'm very sorry, I know this is hard.
I thought that fish mox was still available without prescription, that's a bummer.
Can you link the page you're speaking of? Anyone can put a page up here, unfortunately, it doesn't mean it's true.
An infection hasn't caused the laying issues, the laying...
She doesn't have coccidiosis so corid would be useless and would make the wry neck worse. There's a enough selinium in egg yolks, if she'll eat them.
Any b vitamins you give will cancel out the Corid and vice versa. You don't give them close together for future note.
It's likely a reproductive...
You can get it from pet shops or chewy.
Infection don't cause wry neck, that's a seperate issue that's easily treated. Your bird has two seperate issues which may be caused by the same thing.
Treat wry neck with 400i.u vitamin E and a third of a B complex tablet everyday.