Ronidazole for 5lb hen?

[finnleywren]

Hello backyard community. I’m wondering if anyone here has heard of a Ronidazole suspension which can be purchased online? And what the dosing might be for a 5lb hen. She is being treated with metronidazole for canker and it is not working. I’m seeing powder and tablets online but I’m not seeing suspension. She is under an avian vet’s care. I’m hoping to find a cheaper alternative online. Many thanks in advance.