Just the chick starter. No grit. Grit is never mixed with feed. It should only ever be offered on the side for free choice feeding but your hen does not need it when only each starter and being treated. Just give her the treated water and the mash you make of her chick starter. Nothing else. For...
I would confine her in a large dog crate in the run so she is still near the other birds and treat her with acidified copper sulfate (ACS).
To dilute the ACS, using a kitchen scale, you would weigh out 1/2 pound (227 g) of the ACS and dissolve it in a gallon of clean water. This is the...