The bar spacing for a African grey can be no smaller then 3/4" and no larger then 1"
The wire will also need to be powder coated or stainless steal otherwise it will not be safe. This is why cage wires are covered because the wire underneath is toxic to birds. African greys will need powder coated wires because there beak is very strong and can easily chip away the paint.
NO I THINK U CANT BECAUSE IT CAN MAKE A HOLE N FLY AWAY
I have those sort of bunny cage mesh things and I want to build a cage for my African grey, is it suitable?