There are no universal floorings that I am aware of. Most bird cage companies make gratings that are specifically made for their cages. I have removed the gratings from my personal birds cages because they love to get down and rip up the newspapers that I put down. I feel that relieves boredom.
I dont know about mesh, but most cages have a floor that slides in and out for cleaning, then put paper down which birds chew and hide under
No no parts sold, only cages.
Thanks! Your answer is awaiting moderation.